<unk> s are<unk>  compounds with a<unk>  host   . In this type of compound the<unk>  layers remain largely intact and the guest molecules or atoms are located in between. When the host and the guest interact by charge transfer the in-plane  electrical conductivity generally increases. When the guest forms covalent bonds with the<unk>  layers as in fluorides or oxides the conductivity decreases as the conjugated sp² system collapses. In a<unk>  not every layer is necessarily occupied by guests. In so-called stage 1 compounds<unk>  layers and intercalated layers alternate and in stage 2 compounds two<unk>  layers with no guest material in between alternate with an intercalated layer. The actual composition may vary and therefore these compounds are an example of non-stoichiometric compounds. It is customary to specify the composition together with the stage.
Potassium<unk>  is denoted as KC8 and is one of the strongest reducing agents known. It is prepared under inert atmosphere by melting potassium over<unk>  powder. The potassium is absorbed into the<unk>  and a color change from black to bronze is observed. The resulting solid is also quite pyrophoric. Structurally, composition can be explained by assuming that the potassium to potassium distance is twice the distance between hexagons in the carbon framework. The bond between<unk>  and potassium atoms is ionic and the compound is electrically conductive. .
Potassium<unk>  has also been used as a catalyst in polymerizations and as a coupling reagent for aryl halides to biphenyls .
In one study  freshly prepared KC8 is treated with 1-iodododecane delivering a modification (micrometre scale carbon platelets with long alkyl chains sticking out providing solubility) that is soluble in chloroform. Another potassium<unk>  compound, KC24, has been used as a neutron monochromator.
Carbon monofluoride is denoted as (CF)x and used as a cathode material in a type of lithium batteries. It is prepared by reaction of gaseous fluorine with<unk> c carbon at 420-450 °F. The color is grayish, white, or yellow. The bond between the carbon and fluorine atoms is covalent. The compound is not electrically conductive.
Tetracarbon monofluoride is denoted as C4F. It is prepared by reacting gaseous fluorine mixed with hydrogen fluoride with<unk>  at room temperature. The compound has blackish-blue color.
Other examples are<unk>  bisulfate and<unk>  oxide.
Examples of complex<unk> s are those with barium and ammonia guests (Ba(NH3)2.5C10.9(st.1)) or those with caesium, hydrogen and potassium  (CsC8.K2H4/3C8(st.1)).
Graphite intercalation compound
Antimetabolite
Sulfa drug
Clathrate compound
Beta-lactamase inhibitor
Aminoglycoside antibiotic
Glycopeptide antibiotic
Protic solvent