p 219 (C=X)X group 220 C-O-C group 221 C-OH group 222 Aryl-OH group 223 Two or more N-C=X groups or two or more C-OH groups 224 At least one solid polymer derived from ethylenic reactants only 225 Atom other than N, C, H, or oxygen 226 Carbocyclic group 227 Two or more N-C=O groups 228 At least one solid polymer derived from ethylenic reactants only 229 At least one solid polymer derived from acyc