Thioxo

Part of speech: adjective

Definitions

1. Describing a chemical compound or group that contains a sulfur atom double-bonded to a carbon atom, as used in organic chemistry nomenclature
2. Referring to a molecular structure in which a sulfur atom is doubly bonded to a carbon, a feature named in chemical naming systems
3. Characterizing an organic molecule bearing a carbonyl-type group where sulfur replaces oxygen, a term used in chemical nomenclature

Etymology: "Thioxo" is a chemistry term built from two Greek-derived pieces. The first, "thio-", comes from Greek "theion," meaning sulfur, and it appears in chemical names wherever sulfur replaces oxygen in a molecule. The second, "-oxo," is the chemists' shorthand for an oxygen atom double-bonded to a carbon, so a thioxo group is the sulfur counterpart of a carbonyl group, with C=S in place of C=O. Both pieces are nineteenth-century systematic chemical nomenclature rather than ancient vocabulary. Chemists coined "oxo" and its relatives as they standardized naming conventions, so the word was not used by the Greeks, who had the root "theion" for sulfur but no notion of double bonds. The word therefore records a modern naming system built from old roots, rather than a survival from antiquity.