Trioxide

Part of speech: noun

Pronunciation: /trʌɪˈɒksʌɪd/

Definitions

1. A chemical compound that consists of three oxygen atoms bonded to another element or group
2. A substance formed with three atoms of oxygen in its molecular structure, often exhibiting various properties
3. An oxide characterized by the presence of three oxygen atoms combined with a different chemical element or radical

Etymology: "Trioxide" is a plain compound: "tri-", from Greek "treis" meaning three, added to "oxide". The "tri-" prefix is a productive chemical-naming element, used to count atoms in a formula, so a trioxide is a compound whose molecule contains three oxygen atoms per unit of the other element, as in "sulfur trioxide" or "aluminium trioxide" in some naming styles. The base word "oxide" is the more interesting part. It was built from "oxygen", a name coined in French as "oxygène" by Antoine Lavoisier in the 1770s, combining Greek "oxús", meaning sharp or acid, with "-genēs", meaning producing. Oxygen was named for its supposed role in forming acids, which chemists then believed it always did. "Oxide" follows the same pattern, using the "-ide" ending that was borrowed into chemical nomenclature from the French "oxyde", itself modelled on the "oxygène" coinage.

Synonyms: oxide, compound