a cyclic or ring structure in which one or more of the atoms in the ring is an element other than carbon, forming compounds such as amine, pyridine, pyrrole, furan, etc.
A cyclic or ring structure in which one or more of the atoms in the ring is an element other than carbon. (Common heterocyclics are pyridine, pyrrole, furan, thiophene, and purine.)
A type of organic compound in which the characteristic chemical groups are linked in a closed ring structure and in which one or more atoms in the ring is an element other than carbon, e.g., silica, sulfur, nitrogen, etc.