| a chattering or flighty, light-headed person. |
| a printed punctuation mark (‽), available only in some typefaces, designed to combine the question mark (?) and the exclamation point (!), indicating a mixture of query and interjection, as after a rhetorical question. |
| benzene ring | |
| —n | |
| See also Kekulé formula Also called: benzene nucleus the hexagonal ring of bonded carbon atoms in the benzene molecule or its derivatives | |
benzene ring n.
The hexagonal ring structure in the benzene molecule and its substitutional derivatives, each vertex of which is occupied and distinguished by a carbon atom.
benzene ring
(click for larger image in new window) A hexagonal arrangement of six carbon atoms, each atom bonded to its adjacent atoms by a single covalent bond, and by an unusual ring bond of electrons shared by all six carbon atoms. The benzene ring is a basic component of many organic compounds, especially the aromatic hydrocarbons. In benzene itself, each carbon atom is also bonded to a hydrogen atom; in derivatives of benzene, one or more of the hydrogen atoms is replaced by other atoms or groups of atoms. |