circular dichroism (CD), 275 cis, trans , 275 cis conformation in polymers , 276 cis- in inorganic nomenclature , 276 cis-fused, 276 cis-trans isomers, 277 cisoid conformation [obsolete] , 277 cistactic polymer, 277 class (a) metal ion, 277 class (b) metal ion, 278 class of helix in polymers , 278 clathrates, 278 clausius, 278 clay hybrid, 278 clean surface, 279 clean up in spectrochemical analysis , 279 clearance, , 279 clearance in toxicology , 279 clearing point, 280