III. The integrity of published information: Validating a small-unit-cell structure; understanding checkCIF reports
Linden, Anthony
When small structures are submitted for publication in IUCr journals, they are analysed as part of the peer review process by the software suite checkCIF. The goal of this analysis is to provide an objective assessment of the quality and reliability of the published structure, with reference both to the available experimental data and the level of consistency with known chemistry. For this to work well, validation protocols have to keep up with advances in structure determination methodologies. Consequently, it is important that CIF tools and definitions are both practical and extended and revised regularly. The purpose and output of validation also have to be understood easily by users, reviewers and journal editors, some of whom may not be expert crystallographers.
 Good afternoon everybody and thank you Brian for the invitation to speak this afternoon. Mike observed that I had rather a lot of slides in this talk and I've just reduced them by a third because he has covered some of these already so I apologize for any duplication. Let's think about history here for a moment. Who remembers what it was like when we didn't have motor cars in the world? I guess nobody, right? Who remembers what it was like when we didn't have SIF? A few hands, but if you're younger than about 45 years old, you only ever grew up with SIF. Think what it was like when we had to publish data before we had the SIF facility available. For start, a lot of papers were submitted on typewritten sheets so you had to transcribe data from one place to the other. Maybe you had a funny little floppy disk at some stage. How did we know that everything had been done correctly? How do we validate things? Back then, one crystal structure in the small molecule world took some days, maybe even months before you published it. We had a lot of time and we had to do a lot of things very manually. As you were doing things manually, you tended to check things as you were going. Validation was part of your life at that time. Now things are going a lot faster. We have data sets every couple of hours. We have data sets every 10 seconds in some facilities. It's very hard to find enough time to think about all of these things carefully and observe everything. So we have tools to help us validate what we are doing to avoid making goofs and egg on face situations when you are publishing data. We have heard before in 1991 came the paper by Sid Hall and others which defined the initial phase of SIF. That was great. I picked that paper up. I read it from front to back and I really enjoyed it. Very quickly I was submitting papers in SIF format to actor Chris C. I probably only published one or two structures prior to that. There was a big spike in my output simply because I didn't have to worry about the crystallographic data anymore. I only had to type a few sentences to describe my structure, to describe the science. The utility of all that wouldn't have happened had not, and I guess I've heard someone say already, Sid was very persuasive. He got people on board with the software in the small molecule world to get SIF incorporated and therefore you could use it. The users could use it. That enabled the journal to start saying, hey, you can submit things in SIF and a bit later, hey, you must submit things in SIF. So it went on. Then Sid Hall had the idea, well, you know, some things not really right with these submissions. Perhaps they should be checked more thoroughly and the guys in the chest of the editorial staff were doing a lot of that manual checking, as Mike said. Why not automate that, put it back and let the authors use some tool to validate their work. It saves them submitting stuff and having to resubmit it and resubmit it. They do all that before they get to submission. So validation was born. Mike Hoyland developed some things in Chester. Tom Speck was brought on board and between them over the years they have developed a very comprehensive validation tool. This is Brian said earlier, you know, this is not about validation, but this is about SIF and see what it's become over the years. So why do we need check SIF? Well, when my timer comes through, there we go, we got those CCD detectors in particular, area detectors around 1994 when Brooker released their smart system. And so the numbers of structures we were generating went up dramatically. The speed went up dramatically. Software developers started to write nice graphical user interfaces, especially the diffractometer companies. So, you know, we were able to click buttons and do pretty things and have pretty pictures and instant refinements. But what that tends to do is it stops people looking at the output files, at the LST or the log files and the information about, hey, hang on a minute, there's something not quite right here, is in those files and not on the screen and so it's lost. And people tend to miss out on it. So, you know, you need other ways to prompt people. Crystallography became so easy, there were more what I call non-experts. People who are not in this room who are expert crystallographers or have done, doing crystallography as a career, they might be chemists or physicists or whatever, using crystallography as a tool. They're doing it quite competently, but they perhaps lack the formal training so they can easily have oversight to make mistakes. You can also use the validation to set the standards you want. In other words, encourage best practice. Whether you agree with the standards Chexif has promulgated, it doesn't really matter. But these are, this is where to aim. If you can aim up there, you have a consistent target for everybody. If you, you know, different structures behave differently, you can't always meet that target, but that's the aim. It's a consistent thing. Authors don't need to revise as much if they have more flawless submissions and ultimately this goes through to rapid, more rapid publication, which is what everybody likes. Well, I can skip this slide because Mike showed that, you know, we're testing against a whole series of different criteria. We look for the SIF itself being a consistent file and there's not mistakes that kill the syntax of the SIF space groups, symmetry, and isotropic displacement parameters that all of the derived parameters are consistent, geometric parameters, bond lengths, angles, errors, and even the reflection data as Mike talked about, the structure factors and a whole lot more things. This Chexif program is really out there to help everybody. It's to help you to check your work, make sure everything's okay, to follow best practice ideals. It's not designed as a, I'm sorry, you can't publish in this journal, right? There's not a brick wall, but a lot of people unfortunately got that impression when it came out. That's not really true. Okay? If you can't meet the criteria, that's okay provided there's a good scientific understanding of the reason why you don't get there. And at the same time, reviewers can use this. So if you're, you know, the viewers on the other foot sometimes you are reviewing papers and it's a tool to help you look at what the authors have been doing. There's many sources of outlier parameters, incorrect structures, some feature like disorder that you haven't treated fully, could lead to validation alerts, or you're using some non-optimal procedures that should be done better. You can go through a whole list of these things, or it could be some real observation that's unusual and hey, if that's the case, then it's a good thing to discuss. You might say, well, you know, we've made everybody aware of the need for validation and so on, and do we still need it? Probably yes, because even in publications in various journals today there are problems. Okay? This comes from inexperience or just plain laziness, ignoring some of the less severe alerts even though they're not severe, they might still mean something or just not being able to understand the alerts properly. And then there's two problems, blind reliance on checks. If there's no alert, there's no problem. Are you sure? Okay? Others tend to do the other thing, oh, there's an alert, I'm sorry, there must be something wrong. And so people need to learn a little bit more to understand what these alerts are telling you. Another issue is the generation of new instruments that are fully automated and the software that the diffractometer companies like to sell is, hey, you can just drop a crystal in, bang, you get out a pretty picture in the end, you don't need much experience to do it. Are you really sure? For my diffractometer, I have one of these automated structure solution refinement things and it works really well. It's a great tool, but a certain percentage of structures, it still gets element assignments mixed up. It's not always possible to distinguish carbon and nitrogen and so on. So you need a little bit of expertise and knowledge to make sure it's doing the job correctly. So Mike showed you how to upload a SIF into the system at the ChexSIF site. You get feedback, which gives you a summary at the beginning and then some of the alerts. And one feature of that is you get some alerts and you don't understand the text. It's very short. If we made a long description for each of those, the web page would go on and on and on. So it's kept short, but they are clickable. So if you click on these alerts there, then up should pop a window, which gives you a little bit of help to interpret what's going on. At the bottom you get just an ellipsoid plot, which is created out of the SIF and not something that somebody has created by another route. Alternatively, you can use plate on itself. Plate on will actually have a few more tests switched on in it that in Chester we disable. So if you want to really be thorough, you can use plate on itself. It works the same way. You click the, I don't have my pointer here. Where is the pointer? You click the validation button up there and it just runs the suite. The output you get back looks much the same as what you get from the online version of Chexsiv. So then we get this feedback with alert in it. There's three types of alert indicators. There's this ABC and actually G, which tells you something about the severity of the alert. There's another one here, an alert number, which was introduced a bit later on, which tries to tell you about the type of alert. This might give you a hint as to what's really necessary here. Type one tells you there's a syntax error in the SIF. It's usually trivial, should be easy to correct. Type two says, hey, there's a hint here that your model might not be quite correct. Type three says, it's not really the problem with the model, but the data overall are not of the greatest quality. The other two are really just information or maybe suggestions that you might be able to do things in a slightly different way that might lead to a more optimal result. So if you get an A alert, this is usually quite serious and needs to be attended to or thought about. And it could be trivial. I mean, you miss out the crystal dimensions. It's nothing really major, but it's a requirement for the journal publication. So it's a serious alert. Easy to fix. Other things may be not so easy to fix, but you have to decide, is this really, in my case, something I can't do anything about. It's a property of the structure. If so, okay, and I'll tell you how to indicate that in a moment. B, well, it's a little bit less serious, but I think you still should have a look at it. I'm not going to go through that in detail. C tends to be, well, it's not too bad. It's a little bit of an outlier. Well, if it's there, it's something to be thought about. Moiety formula not given. Well, that's okay. You can give it easily to correct. There's a short contact here. Well, maybe that's okay. Small ADP for an atom. It's only slightly different. So each of those individually might be, well, not too bad, but what happens if we consider those three together? What could that mean? Well, if you have the pyridinium cation, it probably means that you've switched the position of the nitrogen. Because it's very difficult to work out where this guy, when he's positively charged, should lie, but this distance here is probably from here. And so that's a hydrogen bond. So if the nitrogen was in the other position, then all these alerts would go away. There is this G alert now that is actually increasing in the number of categories that give that alert. It's not necessarily an error. It's a prompt to say, are you sure? Okay, but you should think about those. We've seen that procedure from Mike, so I won't go through that one again. The thing is you get a list of validation alerts. It's important to try and address each one, look at each one, and think about it for a few seconds to decide is it important, is it something I can easily deal with? If it is, deal with it. The criteria are based on what we'd say are normally expected. There are many cases where the normal situation won't apply, but it's up to you to understand that. And the benefits are that you can get things through the publication process much more quickly. So if you've still got trouble with A and B alerts and you know you can't resolve that, then all you have to do is say, okay, I know what's wrong there, and you put in a short explanation and it doesn't have to be a page. Just explain why this is a true feature. Now maybe that should be in the experimental section of your paper. We're supposed to be documenting our scientific observations and results and procedures. It doesn't have to be in an excuse filled into the SIF, but it should be put in the appropriate place. And some of the appropriate places, if it's not in your paper, would be in such sections of the SIF. So if you get this level A, then what you get back from the system is a validation reply form which you just plug into your SIF and you fill in this response line here and you can give an answer. When you've done that, if you rerun check SIF, the answer appears in the check SIF output. Now the handiness of that is you can see you've done something and the second thing is a reviewer can see that you've done something. So there it is for everybody to see. Our validation is not the be all and end all, there are limits, maybe there's some test we haven't yet thought about implementing. If you think of something, let Tom know. It may not be practical to apply that test in a computer program. So you still have to be a little bit careful and be vigilant yourself when you're checking your own structures. Other things you can put in the SIF which make no sense, like you can say an iron too complex has a certain color which has got nothing, never have anything to do with iron too, right? But you can't validate that so easily. So you have to say, does the structure make sense to you? Does the structure look right? When you look at the ellipsoid plot from all angles, they're strange ellipsoids. These often give you a visual impression very quickly of odd things. Does the chemistry match the structure? Or if the structure is something different, can you understand how you got there with the chemistry? If you're using restraints in a difficult structure, don't overly restrain the structure to be that which you wanted to be and not that which it is trying to be. Be careful about that. You can even use the databases. CSD has a lot of information about certain geometries which you can use to compare with your structure and see that everything's okay. And look at the listing files, the output files, the log files as well if you've got problems. I just want to give two examples here, a situation where somebody had four lactams. Four lactams. But one was claimed to be a rather rarely-senium-mitic acid tortimer. So here instead of NH and carbonyl here, we have OH and an N here. Well is it really? The R factor on that structure was 0.059. For an organic molecule, no, it's okay. Nothing unusual there. But there is a B alert. Hirschfeld test says there's something wrong with the ellipsoids, the ADPs of two atoms that are bonded together. So there's a problem for that O1C2 bond, which is this supposed to be this carbonyl, or it's an OH in this model. And there's a peak which is slightly larger, residual peak, than the rest. And so if you run a different density map, you see here there's a lot of negative electron density around this oxygen, and there's a slight this peak here, that's this one, comes up here. So what is it? Well, instead of OH, it's NH2. That peak was another hydrogen missing, and now if we change the oxygen to a nitrogen, that negative electron density goes away. The R factor drops a little bit to 0.046. So that's the answer. Of course, the chemist now has to understand what's gone wrong in their synthesis. The second example we have here, a strange thing, which this should be a CH2 group, apparently, it's missing a hydrogen. And it actually only generates a G alert saying, well, the angles are a bit odd here, for if only one hydrogen, then it should be a planar, and it's not planar, obviously. So what's gone wrong there? The largest peak is here in the difference map, 0.84 electrons per cubic angstrom. So there's definitely a missing hydrogen in the model. Okay, can happen, right? But in the SIF there's no mismatched formula. So what's happened here is the author decided, well, there was a mismatched formula, so I've changed the formula, so it matches my model. Okay, that went away. And in fact, the author said, the structure's fine because there's no serious alert in Chexiv. You'd be the judge. Okay. Then comes structure factor validation, which has only been around a few years now, and it was one of the reasons we could pick up on the fraud. But it can find all sorts of things like mismatch between the data block names in the SIF and the FCF file. Well, if they missed, it just means someone's uploading the wrong pair of files. It happens, it's not uncommon. Or structure factor file's not from the same refinement that produced the SIF. Someone's done some updating of a SIF and it's got out of kilter somehow. Miss twinning can be found. Someone does a transformation and pastes in new atomic coordinates, but doesn't transform the UIJ. I mean, this cut and paste business of stuff into the SIF instead of just generating a completely fresh new one is a problem. And other sorts of things that can be done, including cheating. This is a synthetic example. There's a water molecule which is emitted from the refinement used to generate the FCF file, but it was in the model to generate the SIF. And you can see that you get mismatches all over the place of r-factors and lots of alerts saying there's problems with the r-factors and goodness of fit and the reported and calculated density and all sorts of things. So that's a fairly clear sign that there was some mismatch there. As I said a bit earlier, you start editing into the guts of a SIF. That's a bad thing to do and hopefully if you find a problem, rerun the refinement, generate a nice fresh SIF and then all of these sorts of things go away. Now I just want to finish off on, this is a session on SIF and hey, SIF is a great tool. As I said at the beginning, a lot of people, young people don't know what life was like without SIF. The problem is the better you make something, the easier you make something concerning computer programs, the more the user gets upset as soon as it doesn't work properly, right? So SIF as for the user is only as good as its acceptance by the users. It needs to be useful, it needs to be easy to use, it needs almost to be transparent, especially for people who are not specialists in the field. Now over the last year or so at the IUCR, journals were been looking into trying to improve the journals, make them more attractive to authors. One of the things I've been doing at Act of Christy is trying to find out how we could attract more authors to Section C. Chemists are quite reluctant at the moment to publish in Section C and so you say, well why? There are a number of reasons but one is SIF is too hard to understand or work with or do, they cannot prepare a paper in SIF. That means, may seem to some people incredulous. Yet, that is the attitude of the chemical community or parts of the chemical community. So we have to be careful about that. We have PublSIF, we have in SIFA, PublSIF is a great tool, yet there are people in the community who say, I want to use word, I have not time to learn PublSIF as easy as it is, word or nothing. Why? Are people not as capable with computers as they were 25 years ago? I don't know. Anyway, what this has led to, unfortunately with Act of Christy is we have recently decided that we will accept the text sections of a C paper as a word document. It seems a bit sad to go that way but it seems some authors will not submit unless that happens. The other thing is there is a tendency at the moment for a proliferation of non-defined, non-standard data names in SIFs. You're allowed to do that. The SIF context allows you to do that. However, it's getting away from us a little bit. It's getting a little bit out of hand. I urge ComSIFs, perhaps they need to take this back to themselves and try and cooperate with or negotiate with software developers and others to get these things organized more better, otherwise we'll have a plethora of things that nobody knows the definitions for. Each diffractometer manufacturer has a different sequence of things for the same data. I would encourage ComSIFs to actively go out there and talk to the software developers. There are things that we use these days in the small molecule science that weren't very often used way back 20 years ago and there are no SIF definitions for them. We need to have those and we need to be able to get them quickly. I'm happy if a data name caters for 98% of the situations and the other 2% we can work on later. If we delay while we try and work out how to cater for 100%, it's a bit difficult. Some of the SIF definitions, existing ones, they need to be curated a little bit and gone over to make sure they still are good for things that we use today. For example, the items that deal with absorption because we don't just do numerical absorption corrections anymore, we have these programs that treat CCD data and do all sorts of corrections and we have one item for it and we need more items for those sorts of things. I don't mean to be negative here but I think one needs to pay a little bit more attention to these things. That's all I have to say. I won't even read my summary, I think you can read it, except that structure factors are very important and I hope that in the coming years we can encourage non-crystallographic journals to also require structure factors to always be submitted. George's new version of his program puts the raw data automatically into the SIF, which is a good step in the right direction. Thank you very much. Thank you.
 Good afternoon everybody and thank you Brian for the invitation to speak this afternoon.  Mike observed that I had rather a lot of slides in this talk and I've just reduced them by  a third because he has covered some of these already so I apologize for any duplication.  Let's think about history here for a moment.  Who remembers what it was like when we didn't have motor cars in the world?  I guess nobody, right?  Who remembers what it was like when we didn't have SIF?  A few hands, but if you're younger than about 45 years old, you only ever grew up with SIF.  Think what it was like when we had to publish data before we had the SIF facility available.  For start, a lot of papers were submitted on typewritten sheets so you had to transcribe  data from one place to the other.  Maybe you had a funny little floppy disk at some stage.  How did we know that everything had been done correctly?  How do we validate things?  Back then, one crystal structure in the small molecule world took some days, maybe even  months before you published it.  We had a lot of time and we had to do a lot of things very manually.  As you were doing things manually, you tended to check things as you were going.  Validation was part of your life at that time.  Now things are going a lot faster.  We have data sets every couple of hours.  We have data sets every 10 seconds in some facilities.  It's very hard to find enough time to think about all of these things carefully and observe  everything.  So we have tools to help us validate what we are doing to avoid making goofs and egg  on face situations when you are publishing data.  We have heard before in 1991 came the paper by Sid Hall and others which defined the initial  phase of SIF.  That was great.  I picked that paper up.  I read it from front to back and I really enjoyed it.  Very quickly I was submitting papers in SIF format to actor Chris C. I probably only published  one or two structures prior to that.  There was a big spike in my output simply because I didn't have to worry about the crystallographic  data anymore.  I only had to type a few sentences to describe my structure, to describe the science.  The utility of all that wouldn't have happened had not, and I guess I've heard someone say  already, Sid was very persuasive.  He got people on board with the software in the small molecule world to get SIF incorporated  and therefore you could use it.  The users could use it.  That enabled the journal to start saying, hey, you can submit things in SIF and a bit later,  hey, you must submit things in SIF.  So it went on.  Then Sid Hall had the idea, well, you know, some things not really right with these submissions.  Perhaps they should be checked more thoroughly and the guys in the chest of the editorial  staff were doing a lot of that manual checking, as Mike said.  Why not automate that, put it back and let the authors use some tool to validate their  work.  It saves them submitting stuff and having to resubmit it and resubmit it.  They do all that before they get to submission.  So validation was born.  Mike Hoyland developed some things in Chester.  Tom Speck was brought on board and between them over the years they have developed a  very comprehensive validation tool.  This is Brian said earlier, you know, this is not about validation, but this is about  SIF and see what it's become over the years.  So why do we need check SIF?  Well, when my timer comes through, there we go, we got those CCD detectors in particular,  area detectors around 1994 when Brooker released their smart system.  And so the numbers of structures we were generating went up dramatically.  The speed went up dramatically.  Software developers started to write nice graphical user interfaces, especially the diffractometer  companies.  So, you know, we were able to click buttons and do pretty things and have pretty pictures  and instant refinements.  But what that tends to do is it stops people looking at the output files, at the LST or  the log files and the information about, hey, hang on a minute, there's something not quite  right here, is in those files and not on the screen and so it's lost.  And people tend to miss out on it.  So, you know, you need other ways to prompt people.  Crystallography became so easy, there were more what I call non-experts.  People who are not in this room who are expert crystallographers or have done, doing crystallography  as a career, they might be chemists or physicists or whatever, using crystallography as a tool.  They're doing it quite competently, but they perhaps lack the formal training so they can  easily have oversight to make mistakes.  You can also use the validation to set the standards you want.  In other words, encourage best practice.  Whether you agree with the standards Chexif has promulgated, it doesn't really matter.  But these are, this is where to aim.  If you can aim up there, you have a consistent target for everybody.  If you, you know, different structures behave differently, you can't always meet that target,  but that's the aim.  It's a consistent thing.  Authors don't need to revise as much if they have more flawless submissions and ultimately  this goes through to rapid, more rapid publication, which is what everybody likes.  Well, I can skip this slide because Mike showed that, you know, we're testing against a whole  series of different criteria.  We look for the SIF itself being a consistent file and there's not mistakes that kill the  syntax of the SIF space groups, symmetry, and isotropic displacement parameters that  all of the derived parameters are consistent, geometric parameters, bond lengths, angles,  errors, and even the reflection data as Mike talked about, the structure factors and a  whole lot more things.  This Chexif program is really out there to help everybody.  It's to help you to check your work, make sure everything's okay, to follow best practice  ideals.  It's not designed as a, I'm sorry, you can't publish in this journal, right?  There's not a brick wall, but a lot of people unfortunately got that impression when it  came out.  That's not really true.  Okay?  If you can't meet the criteria, that's okay provided there's a good scientific understanding  of the reason why you don't get there.  And at the same time, reviewers can use this.  So if you're, you know, the viewers on the other foot sometimes you are reviewing papers  and it's a tool to help you look at what the authors have been doing.  There's many sources of outlier parameters, incorrect structures, some feature like disorder  that you haven't treated fully, could lead to validation alerts, or you're using some  non-optimal procedures that should be done better.  You can go through a whole list of these things, or it could be some real observation that's  unusual and hey, if that's the case, then it's a good thing to discuss.  You might say, well, you know, we've made everybody aware of the need for validation  and so on, and do we still need it?  Probably yes, because even in publications in various journals today there are problems.  Okay?  This comes from inexperience or just plain laziness, ignoring some of the less severe  alerts even though they're not severe, they might still mean something or just not being  able to understand the alerts properly.  And then there's two problems, blind reliance on checks.  If there's no alert, there's no problem.  Are you sure?  Okay?  Others tend to do the other thing, oh, there's an alert, I'm sorry, there must be something  wrong.  And so people need to learn a little bit more to understand what these alerts are telling  you.  Another issue is the generation of new instruments that are fully automated and the software  that the diffractometer companies like to sell is, hey, you can just drop a crystal in,  bang, you get out a pretty picture in the end, you don't need much experience to do it.  Are you really sure?  For my diffractometer, I have one of these automated structure solution refinement things  and it works really well.  It's a great tool, but a certain percentage of structures, it still gets element assignments  mixed up.  It's not always possible to distinguish carbon and nitrogen and so on.  So you need a little bit of expertise and knowledge to make sure it's doing the job  correctly.  So Mike showed you how to upload a SIF into the system at the ChexSIF site.  You get feedback, which gives you a summary at the beginning and then some of the alerts.  And one feature of that is you get some alerts and you don't understand the text.  It's very short.  If we made a long description for each of those, the web page would go on and on and  on.  So it's kept short, but they are clickable.  So if you click on these alerts there, then up should pop a window, which gives you a  little bit of help to interpret what's going on.  At the bottom you get just an ellipsoid plot, which is created out of the SIF and not something  that somebody has created by another route.  Alternatively, you can use plate on itself.  Plate on will actually have a few more tests switched on in it that in Chester we disable.  So if you want to really be thorough, you can use plate on itself.  It works the same way.  You click the, I don't have my pointer here.  Where is the pointer?  You click the validation button up there and it just runs the suite.  The output you get back looks much the same as what you get from the online version of  Chexsiv.  So then we get this feedback with alert in it.  There's three types of alert indicators.  There's this ABC and actually G, which tells you something about the severity of the alert.  There's another one here, an alert number, which was introduced a bit later on, which  tries to tell you about the type of alert.  This might give you a hint as to what's really necessary here.  Type one tells you there's a syntax error in the SIF.  It's usually trivial, should be easy to correct.  Type two says, hey, there's a hint here that your model might not be quite correct.  Type three says, it's not really the problem with the model, but the data overall are not  of the greatest quality.  The other two are really just information or maybe suggestions that you might be able  to do things in a slightly different way that might lead to a more optimal result.  So if you get an A alert, this is usually quite serious and needs to be attended to or  thought about.  And it could be trivial.  I mean, you miss out the crystal dimensions.  It's nothing really major, but it's a requirement for the journal publication.  So it's a serious alert.  Easy to fix.  Other things may be not so easy to fix, but you have to decide, is this really, in my  case, something I can't do anything about.  It's a property of the structure.  If so, okay, and I'll tell you how to indicate that in a moment.  B, well, it's a little bit less serious, but I think you still should have a look at it.  I'm not going to go through that in detail.  C tends to be, well, it's not too bad.  It's a little bit of an outlier.  Well, if it's there, it's something to be thought about.  Moiety formula not given.  Well, that's okay.  You can give it easily to correct.  There's a short contact here.  Well, maybe that's okay.  Small ADP for an atom.  It's only slightly different.  So each of those individually might be, well, not too bad, but what happens if we consider  those three together?  What could that mean?  Well, if you have the pyridinium cation, it probably means that you've switched the position  of the nitrogen.  Because it's very difficult to work out where this guy, when he's positively charged, should  lie, but this distance here is probably from here.  And so that's a hydrogen bond.  So if the nitrogen was in the other position, then all these alerts would go away.  There is this G alert now that is actually increasing in the number of categories that  give that alert.  It's not necessarily an error.  It's a prompt to say, are you sure?  Okay, but you should think about those.  We've seen that procedure from Mike, so I won't go through that one again.  The thing is you get a list of validation alerts.  It's important to try and address each one, look at each one, and think about it for a  few seconds to decide is it important, is it something I can easily deal with?  If it is, deal with it.  The criteria are based on what we'd say are normally expected.  There are many cases where the normal situation won't apply, but it's up to you to understand  that.  And the benefits are that you can get things through the publication process much more  quickly.  So if you've still got trouble with A and B alerts and you know you can't resolve that,  then all you have to do is say, okay, I know what's wrong there, and you put in a short  explanation and it doesn't have to be a page.  Just explain why this is a true feature.  Now maybe that should be in the experimental section of your paper.  We're supposed to be documenting our scientific observations and results and procedures.  It doesn't have to be in an excuse filled into the SIF, but it should be put in the  appropriate place.  And some of the appropriate places, if it's not in your paper, would be in such sections  of the SIF.  So if you get this level A, then what you get back from the system is a validation reply  form which you just plug into your SIF and you fill in this response line here and you  can give an answer.  When you've done that, if you rerun check SIF, the answer appears in the check SIF output.  Now the handiness of that is you can see you've done something and the second thing is a reviewer  can see that you've done something.  So there it is for everybody to see.  Our validation is not the be all and end all, there are limits, maybe there's some test  we haven't yet thought about implementing.  If you think of something, let Tom know.  It may not be practical to apply that test in a computer program.  So you still have to be a little bit careful and be vigilant yourself when you're checking  your own structures.  Other things you can put in the SIF which make no sense, like you can say an iron too  complex has a certain color which has got nothing, never have anything to do with iron  too, right?  But you can't validate that so easily.  So you have to say, does the structure make sense to you?  Does the structure look right?  When you look at the ellipsoid plot from all angles, they're strange ellipsoids.  These often give you a visual impression very quickly of odd things.  Does the chemistry match the structure?  Or if the structure is something different, can you understand how you got there with  the chemistry?  If you're using restraints in a difficult structure, don't overly restrain the structure  to be that which you wanted to be and not that which it is trying to be.  Be careful about that.  You can even use the databases.  CSD has a lot of information about certain geometries which you can use to compare with  your structure and see that everything's okay.  And look at the listing files, the output files, the log files as well if you've got  problems.  I just want to give two examples here, a situation where somebody had four lactams.  Four lactams.  But one was claimed to be a rather rarely-senium-mitic acid tortimer.  So here instead of NH and carbonyl here, we have OH and an N here.  Well is it really?  The R factor on that structure was 0.059.  For an organic molecule, no, it's okay.  Nothing unusual there.  But there is a B alert.  Hirschfeld test says there's something wrong with the ellipsoids, the ADPs of two atoms  that are bonded together.  So there's a problem for that O1C2 bond, which is this supposed to be this carbonyl, or it's  an OH in this model.  And there's a peak which is slightly larger, residual peak, than the rest.  And so if you run a different density map, you see here there's a lot of negative electron  density around this oxygen, and there's a slight this peak here, that's this one, comes  up here.  So what is it?  Well, instead of OH, it's NH2.  That peak was another hydrogen missing, and now if we change the oxygen to a nitrogen,  that negative electron density goes away.  The R factor drops a little bit to 0.046.  So that's the answer.  Of course, the chemist now has to understand what's gone wrong in their synthesis.  The second example we have here, a strange thing, which this should be a CH2 group, apparently,  it's missing a hydrogen.  And it actually only generates a G alert saying, well, the angles are a bit odd here, for if  only one hydrogen, then it should be a planar, and it's not planar, obviously.  So what's gone wrong there?  The largest peak is here in the difference map, 0.84 electrons per cubic angstrom.  So there's definitely a missing hydrogen in the model.  Okay, can happen, right?  But in the SIF there's no mismatched formula.  So what's happened here is the author decided, well, there was a mismatched formula, so  I've changed the formula, so it matches my model.  Okay, that went away.  And in fact, the author said, the structure's fine because there's no serious alert in  Chexiv.  You'd be the judge.  Okay.  Then comes structure factor validation, which has only been around a few years now, and  it was one of the reasons we could pick up on the fraud.  But it can find all sorts of things like mismatch between the data block names in the SIF  and the FCF file.  Well, if they missed, it just means someone's uploading the wrong pair of files.  It happens, it's not uncommon.  Or structure factor file's not from the same refinement that produced the SIF.  Someone's done some updating of a SIF and it's got out of kilter somehow.  Miss twinning can be found.  Someone does a transformation and pastes in new atomic coordinates, but doesn't transform  the UIJ.  I mean, this cut and paste business of stuff into the SIF instead of just generating a completely  fresh new one is a problem.  And other sorts of things that can be done, including cheating.  This is a synthetic example.  There's a water molecule which is emitted from the refinement used to generate the FCF  file, but it was in the model to generate the SIF.  And you can see that you get mismatches all over the place of r-factors and lots of alerts  saying there's problems with the r-factors and goodness of fit and the reported and calculated  density and all sorts of things.  So that's a fairly clear sign that there was some mismatch there.  As I said a bit earlier, you start editing into the guts of a SIF.  That's a bad thing to do and hopefully if you find a problem, rerun the refinement, generate  a nice fresh SIF and then all of these sorts of things go away.  Now I just want to finish off on, this is a session on SIF and hey, SIF is a great tool.  As I said at the beginning, a lot of people, young people don't know what life was like  without SIF.  The problem is the better you make something, the easier you make something concerning computer  programs, the more the user gets upset as soon as it doesn't work properly, right?  So SIF as for the user is only as good as its acceptance by the users.  It needs to be useful, it needs to be easy to use, it needs almost to be transparent,  especially for people who are not specialists in the field.  Now over the last year or so at the IUCR, journals were been looking into trying to improve  the journals, make them more attractive to authors.  One of the things I've been doing at Act of Christy is trying to find out how we could  attract more authors to Section C. Chemists are quite reluctant at the moment to publish  in Section C and so you say, well why?  There are a number of reasons but one is SIF is too hard to understand or work with or  do, they cannot prepare a paper in SIF.  That means, may seem to some people incredulous.  Yet, that is the attitude of the chemical community or parts of the chemical community.  So we have to be careful about that.  We have PublSIF, we have in SIFA, PublSIF is a great tool, yet there are people in the  community who say, I want to use word, I have not time to learn PublSIF as easy as it is,  word or nothing.  Why?  Are people not as capable with computers as they were 25 years ago?  I don't know.  Anyway, what this has led to, unfortunately with Act of Christy is we have recently decided  that we will accept the text sections of a C paper as a word document.  It seems a bit sad to go that way but it seems some authors will not submit unless that happens.  The other thing is there is a tendency at the moment for a proliferation of non-defined,  non-standard data names in SIFs.  You're allowed to do that.  The SIF context allows you to do that.  However, it's getting away from us a little bit.  It's getting a little bit out of hand.  I urge ComSIFs, perhaps they need to take this back to themselves and try and cooperate  with or negotiate with software developers and others to get these things organized more  better, otherwise we'll have a plethora of things that nobody knows the definitions for.  Each diffractometer manufacturer has a different sequence of things for the same data.  I would encourage ComSIFs to actively go out there and talk to the software developers.  There are things that we use these days in the small molecule science that weren't very  often used way back 20 years ago and there are no SIF definitions for them.  We need to have those and we need to be able to get them quickly.  I'm happy if a data name caters for 98% of the situations and the other 2% we can work  on later.  If we delay while we try and work out how to cater for 100%, it's a bit difficult.  Some of the SIF definitions, existing ones, they need to be curated a little bit and gone  over to make sure they still are good for things that we use today.  For example, the items that deal with absorption because we don't just do numerical absorption  corrections anymore, we have these programs that treat CCD data and do all sorts of corrections  and we have one item for it and we need more items for those sorts of things.  I don't mean to be negative here but I think one needs to pay a little bit more attention  to these things.  That's all I have to say.  I won't even read my summary, I think you can read it, except that structure factors  are very important and I hope that in the coming years we can encourage non-crystallographic  journals to also require structure factors to always be submitted.  George's new version of his program puts the raw data automatically into the SIF, which  is a good step in the right direction.  Thank you very much.  Thank you.
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Good afternoon everybody and thank you Brian for the invitation to speak this afternoon. Mike observed that I had rather a lot of slides in this talk and I've just reduced them by a third because he has covered some of these already so I apologize for any duplication. Let's think about history here for a moment. Who remembers what it was like when we didn't have motor cars in the world? I guess nobody, right? Who remembers what it was like when we didn't have SIF? A few hands, but if you're younger than about 45 years old, you only ever grew up with SIF. Think what it was like when we had to publish data before we had the SIF facility available. For start, a lot of papers were submitted on typewritten sheets so you had to transcribe data from one place to the other. Maybe you had a funny little floppy disk at some stage. How did we know that everything had been done correctly? How do we validate things? Back then, one crystal structure in the small molecule world took some days, maybe even months before you published it. We had a lot of time and we had to do a lot of things very manually. As you were doing things manually, you tended to check things as you were going. Validation was part of your life at that time. Now things are going a lot faster. We have data sets every couple of hours. We have data sets every 10 seconds in some facilities. It's very hard to find enough time to think about all of these things carefully and observe everything. So we have tools to help us validate what we are doing to avoid making goofs and egg on face situations when you are publishing data. We have heard before in 1991 came the paper by Sid Hall and others which defined the initial phase of SIF. That was great. I picked that paper up. I read it from front to back and I really enjoyed it. Very quickly I was submitting papers in SIF format to actor Chris C. I probably only published one or two structures prior to that. There was a big spike in my output simply because I didn't have to worry about the crystallographic data anymore. I only had to type a few sentences to describe my structure, to describe the science. The utility of all that wouldn't have happened had not, and I guess I've heard someone say already, Sid was very persuasive. He got people on board with the software in the small molecule world to get SIF incorporated and therefore you could use it. The users could use it. That enabled the journal to start saying, hey, you can submit things in SIF and a bit later, hey, you must submit things in SIF. So it went on. Then Sid Hall had the idea, well, you know, some things not really right with these submissions. Perhaps they should be checked more thoroughly and the guys in the chest of the editorial staff were doing a lot of that manual checking, as Mike said. Why not automate that, put it back and let the authors use some tool to validate their work. It saves them submitting stuff and having to resubmit it and resubmit it. They do all that before they get to submission. So validation was born. Mike Hoyland developed some things in Chester. Tom Speck was brought on board and between them over the years they have developed a very comprehensive validation tool. This is Brian said earlier, you know, this is not about validation, but this is about SIF and see what it's become over the years. So why do we need check SIF? Well, when my timer comes through, there we go, we got those CCD detectors in particular, area detectors around 1994 when Brooker released their smart system. And so the numbers of structures we were generating went up dramatically. The speed went up dramatically. Software developers started to write nice graphical user interfaces, especially the diffractometer companies. So, you know, we were able to click buttons and do pretty things and have pretty pictures and instant refinements. But what that tends to do is it stops people looking at the output files, at the LST or the log files and the information about, hey, hang on a minute, there's something not quite right here, is in those files and not on the screen and so it's lost. And people tend to miss out on it. So, you know, you need other ways to prompt people. Crystallography became so easy, there were more what I call non-experts. People who are not in this room who are expert crystallographers or have done, doing crystallography as a career, they might be chemists or physicists or whatever, using crystallography as a tool. They're doing it quite competently, but they perhaps lack the formal training so they can easily have oversight to make mistakes. You can also use the validation to set the standards you want. In other words, encourage best practice. Whether you agree with the standards Chexif has promulgated, it doesn't really matter. But these are, this is where to aim. If you can aim up there, you have a consistent target for everybody. If you, you know, different structures behave differently, you can't always meet that target, but that's the aim. It's a consistent thing. Authors don't need to revise as much if they have more flawless submissions and ultimately this goes through to rapid, more rapid publication, which is what everybody likes. Well, I can skip this slide because Mike showed that, you know, we're testing against a whole series of different criteria. We look for the SIF itself being a consistent file and there's not mistakes that kill the syntax of the SIF space groups, symmetry, and isotropic displacement parameters that all of the derived parameters are consistent, geometric parameters, bond lengths, angles, errors, and even the reflection data as Mike talked about, the structure factors and a whole lot more things. This Chexif program is really out there to help everybody. It's to help you to check your work, make sure everything's okay, to follow best practice ideals. It's not designed as a, I'm sorry, you can't publish in this journal, right? There's not a brick wall, but a lot of people unfortunately got that impression when it came out. That's not really true. Okay? If you can't meet the criteria, that's okay provided there's a good scientific understanding of the reason why you don't get there. And at the same time, reviewers can use this. So if you're, you know, the viewers on the other foot sometimes you are reviewing papers and it's a tool to help you look at what the authors have been doing. There's many sources of outlier parameters, incorrect structures, some feature like disorder that you haven't treated fully, could lead to validation alerts, or you're using some non-optimal procedures that should be done better. You can go through a whole list of these things, or it could be some real observation that's unusual and hey, if that's the case, then it's a good thing to discuss. You might say, well, you know, we've made everybody aware of the need for validation and so on, and do we still need it? Probably yes, because even in publications in various journals today there are problems. Okay? This comes from inexperience or just plain laziness, ignoring some of the less severe alerts even though they're not severe, they might still mean something or just not being able to understand the alerts properly. And then there's two problems, blind reliance on checks. If there's no alert, there's no problem. Are you sure? Okay? Others tend to do the other thing, oh, there's an alert, I'm sorry, there must be something wrong. And so people need to learn a little bit more to understand what these alerts are telling you. Another issue is the generation of new instruments that are fully automated and the software that the diffractometer companies like to sell is, hey, you can just drop a crystal in, bang, you get out a pretty picture in the end, you don't need much experience to do it. Are you really sure? For my diffractometer, I have one of these automated structure solution refinement things and it works really well. It's a great tool, but a certain percentage of structures, it still gets element assignments mixed up. It's not always possible to distinguish carbon and nitrogen and so on. So you need a little bit of expertise and knowledge to make sure it's doing the job correctly. So Mike showed you how to upload a SIF into the system at the ChexSIF site. You get feedback, which gives you a summary at the beginning and then some of the alerts. And one feature of that is you get some alerts and you don't understand the text. It's very short. If we made a long description for each of those, the web page would go on and on and on. So it's kept short, but they are clickable. So if you click on these alerts there, then up should pop a window, which gives you a little bit of help to interpret what's going on. At the bottom you get just an ellipsoid plot, which is created out of the SIF and not something that somebody has created by another route. Alternatively, you can use plate on itself. Plate on will actually have a few more tests switched on in it that in Chester we disable. So if you want to really be thorough, you can use plate on itself. It works the same way. You click the, I don't have my pointer here. Where is the pointer? You click the validation button up there and it just runs the suite. The output you get back looks much the same as what you get from the online version of Chexsiv. So then we get this feedback with alert in it. There's three types of alert indicators. There's this ABC and actually G, which tells you something about the severity of the alert. There's another one here, an alert number, which was introduced a bit later on, which tries to tell you about the type of alert. This might give you a hint as to what's really necessary here. Type one tells you there's a syntax error in the SIF. It's usually trivial, should be easy to correct. Type two says, hey, there's a hint here that your model might not be quite correct. Type three says, it's not really the problem with the model, but the data overall are not of the greatest quality. The other two are really just information or maybe suggestions that you might be able to do things in a slightly different way that might lead to a more optimal result. So if you get an A alert, this is usually quite serious and needs to be attended to or thought about. And it could be trivial. I mean, you miss out the crystal dimensions. It's nothing really major, but it's a requirement for the journal publication. So it's a serious alert. Easy to fix. Other things may be not so easy to fix, but you have to decide, is this really, in my case, something I can't do anything about. It's a property of the structure. If so, okay, and I'll tell you how to indicate that in a moment. B, well, it's a little bit less serious, but I think you still should have a look at it. I'm not going to go through that in detail. C tends to be, well, it's not too bad. It's a little bit of an outlier. Well, if it's there, it's something to be thought about. Moiety formula not given. Well, that's okay. You can give it easily to correct. There's a short contact here. Well, maybe that's okay. Small ADP for an atom. It's only slightly different. So each of those individually might be, well, not too bad, but what happens if we consider those three together? What could that mean? Well, if you have the pyridinium cation, it probably means that you've switched the position of the nitrogen. Because it's very difficult to work out where this guy, when he's positively charged, should lie, but this distance here is probably from here. And so that's a hydrogen bond. So if the nitrogen was in the other position, then all these alerts would go away. There is this G alert now that is actually increasing in the number of categories that give that alert. It's not necessarily an error. It's a prompt to say, are you sure? Okay, but you should think about those. We've seen that procedure from Mike, so I won't go through that one again. The thing is you get a list of validation alerts. It's important to try and address each one, look at each one, and think about it for a few seconds to decide is it important, is it something I can easily deal with? If it is, deal with it. The criteria are based on what we'd say are normally expected. There are many cases where the normal situation won't apply, but it's up to you to understand that. And the benefits are that you can get things through the publication process much more quickly. So if you've still got trouble with A and B alerts and you know you can't resolve that, then all you have to do is say, okay, I know what's wrong there, and you put in a short explanation and it doesn't have to be a page. Just explain why this is a true feature. Now maybe that should be in the experimental section of your paper. We're supposed to be documenting our scientific observations and results and procedures. It doesn't have to be in an excuse filled into the SIF, but it should be put in the appropriate place. And some of the appropriate places, if it's not in your paper, would be in such sections of the SIF. So if you get this level A, then what you get back from the system is a validation reply form which you just plug into your SIF and you fill in this response line here and you can give an answer. When you've done that, if you rerun check SIF, the answer appears in the check SIF output. Now the handiness of that is you can see you've done something and the second thing is a reviewer can see that you've done something. So there it is for everybody to see. Our validation is not the be all and end all, there are limits, maybe there's some test we haven't yet thought about implementing. If you think of something, let Tom know. It may not be practical to apply that test in a computer program. So you still have to be a little bit careful and be vigilant yourself when you're checking your own structures. Other things you can put in the SIF which make no sense, like you can say an iron too complex has a certain color which has got nothing, never have anything to do with iron too, right? But you can't validate that so easily. So you have to say, does the structure make sense to you? Does the structure look right? When you look at the ellipsoid plot from all angles, they're strange ellipsoids. These often give you a visual impression very quickly of odd things. Does the chemistry match the structure? Or if the structure is something different, can you understand how you got there with the chemistry? If you're using restraints in a difficult structure, don't overly restrain the structure to be that which you wanted to be and not that which it is trying to be. Be careful about that. You can even use the databases. CSD has a lot of information about certain geometries which you can use to compare with your structure and see that everything's okay. And look at the listing files, the output files, the log files as well if you've got problems. I just want to give two examples here, a situation where somebody had four lactams. Four lactams. But one was claimed to be a rather rarely-senium-mitic acid tortimer. So here instead of NH and carbonyl here, we have OH and an N here. Well is it really? The R factor on that structure was 0.059. For an organic molecule, no, it's okay. Nothing unusual there. But there is a B alert. Hirschfeld test says there's something wrong with the ellipsoids, the ADPs of two atoms that are bonded together. So there's a problem for that O1C2 bond, which is this supposed to be this carbonyl, or it's an OH in this model. And there's a peak which is slightly larger, residual peak, than the rest. And so if you run a different density map, you see here there's a lot of negative electron density around this oxygen, and there's a slight this peak here, that's this one, comes up here. So what is it? Well, instead of OH, it's NH2. That peak was another hydrogen missing, and now if we change the oxygen to a nitrogen, that negative electron density goes away. The R factor drops a little bit to 0.046. So that's the answer. Of course, the chemist now has to understand what's gone wrong in their synthesis. The second example we have here, a strange thing, which this should be a CH2 group, apparently, it's missing a hydrogen. And it actually only generates a G alert saying, well, the angles are a bit odd here, for if only one hydrogen, then it should be a planar, and it's not planar, obviously. So what's gone wrong there? The largest peak is here in the difference map, 0.84 electrons per cubic angstrom. So there's definitely a missing hydrogen in the model. Okay, can happen, right? But in the SIF there's no mismatched formula. So what's happened here is the author decided, well, there was a mismatched formula, so I've changed the formula, so it matches my model. Okay, that went away. And in fact, the author said, the structure's fine because there's no serious alert in Chexiv. You'd be the judge. Okay. Then comes structure factor validation, which has only been around a few years now, and it was one of the reasons we could pick up on the fraud. But it can find all sorts of things like mismatch between the data block names in the SIF and the FCF file. Well, if they missed, it just means someone's uploading the wrong pair of files. It happens, it's not uncommon. Or structure factor file's not from the same refinement that produced the SIF. Someone's done some updating of a SIF and it's got out of kilter somehow. Miss twinning can be found. Someone does a transformation and pastes in new atomic coordinates, but doesn't transform the UIJ. I mean, this cut and paste business of stuff into the SIF instead of just generating a completely fresh new one is a problem. And other sorts of things that can be done, including cheating. This is a synthetic example. There's a water molecule which is emitted from the refinement used to generate the FCF file, but it was in the model to generate the SIF. And you can see that you get mismatches all over the place of r-factors and lots of alerts saying there's problems with the r-factors and goodness of fit and the reported and calculated density and all sorts of things. So that's a fairly clear sign that there was some mismatch there. As I said a bit earlier, you start editing into the guts of a SIF. That's a bad thing to do and hopefully if you find a problem, rerun the refinement, generate a nice fresh SIF and then all of these sorts of things go away. Now I just want to finish off on, this is a session on SIF and hey, SIF is a great tool. As I said at the beginning, a lot of people, young people don't know what life was like without SIF. The problem is the better you make something, the easier you make something concerning computer programs, the more the user gets upset as soon as it doesn't work properly, right? So SIF as for the user is only as good as its acceptance by the users. It needs to be useful, it needs to be easy to use, it needs almost to be transparent, especially for people who are not specialists in the field. Now over the last year or so at the IUCR, journals were been looking into trying to improve the journals, make them more attractive to authors. One of the things I've been doing at Act of Christy is trying to find out how we could attract more authors to Section C. Chemists are quite reluctant at the moment to publish in Section C and so you say, well why? There are a number of reasons but one is SIF is too hard to understand or work with or do, they cannot prepare a paper in SIF. That means, may seem to some people incredulous. Yet, that is the attitude of the chemical community or parts of the chemical community. So we have to be careful about that. We have PublSIF, we have in SIFA, PublSIF is a great tool, yet there are people in the community who say, I want to use word, I have not time to learn PublSIF as easy as it is, word or nothing. Why? Are people not as capable with computers as they were 25 years ago? I don't know. Anyway, what this has led to, unfortunately with Act of Christy is we have recently decided that we will accept the text sections of a C paper as a word document. It seems a bit sad to go that way but it seems some authors will not submit unless that happens. The other thing is there is a tendency at the moment for a proliferation of non-defined, non-standard data names in SIFs. You're allowed to do that. The SIF context allows you to do that. However, it's getting away from us a little bit. It's getting a little bit out of hand. I urge ComSIFs, perhaps they need to take this back to themselves and try and cooperate with or negotiate with software developers and others to get these things organized more better, otherwise we'll have a plethora of things that nobody knows the definitions for. Each diffractometer manufacturer has a different sequence of things for the same data. I would encourage ComSIFs to actively go out there and talk to the software developers. There are things that we use these days in the small molecule science that weren't very often used way back 20 years ago and there are no SIF definitions for them. We need to have those and we need to be able to get them quickly. I'm happy if a data name caters for 98% of the situations and the other 2% we can work on later. If we delay while we try and work out how to cater for 100%, it's a bit difficult. Some of the SIF definitions, existing ones, they need to be curated a little bit and gone over to make sure they still are good for things that we use today. For example, the items that deal with absorption because we don't just do numerical absorption corrections anymore, we have these programs that treat CCD data and do all sorts of corrections and we have one item for it and we need more items for those sorts of things. I don't mean to be negative here but I think one needs to pay a little bit more attention to these things. That's all I have to say. I won't even read my summary, I think you can read it, except that structure factors are very important and I hope that in the coming years we can encourage non-crystallographic journals to also require structure factors to always be submitted. George's new version of his program puts the raw data automatically into the SIF, which is a good step in the right direction. Thank you very much. Thank you.
you had to transcribe data from one place to the published one or two structures prior to that. people on board with the software in the small this room who are expert crystallographers or but it's a requirement for the journal thing is you get a list of validation alerts. easily deal with? If it is, deal with it. The can get things through the publication process results and procedures. It doesn't have to be in put in the appropriate place. And some of the know. It may not be practical to apply that test files, the output files, the log files as well if on that structure was 0.059. For an organic as good as its acceptance by the users. It needs and the other 2% we can work on later. If we definitions, existing ones, they need to be non-crystallographic journals to also require