22667
A small number of very large crystals appear for precipitant concentrations varied over orders of magnitude , ~ 0 . 003 - 0 . 3 M ; for some proteins , crystals appear even without addition of any precipitant , not seen with any other heterogeneous substrates .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
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