Arsenious

Part of speech: adjective

Definitions

1. Belonging to a certain oxidation state, this term indicates compounds that include a chemical element associated with arsenic in its trivalent form
2. This descriptor pertains to substances that are characterized by the presence of arsenic, specifically in the +3 oxidation state
3. Referencing a specific oxidation state, this label applies to compounds that contain arsenic in its trivalent form

Etymology: Arsenious is built from "arsenic" plus the English adjectival suffix "-ous," the same ending found in words like "ferrous" and "sulphurous." The suffix marks a lower of two valences: chemists use "-ous" for the less oxidised form of an element and "-ic" for the more oxidised one. So arsenious describes the trivalent state of arsenic, while arsenic acid, with its higher oxidation, takes the "-ic" ending. The name of the parent element carries its own old story. "Arsenic" comes into English through Latin "arsenicum" from Greek "arsenikon," a word for the yellow pigment orpiment, and the Greek term may itself have been borrowed from an Iranian source. The chemistry of arsenic was long confused with that of other substances, which is why the adjective family exists at all: chemists needed systematic names to separate its compounds by oxidation state.

Synonyms: arsenic-based