Words / B2

dy-OKS-yd/daɪˈɒksaɪd/

A dioxide is a compound of two oxygen atoms with another element: carbon dioxide; sulphur dioxide. This entry is the chemistry word, not a loose climate slogan. Carbon (already in B2) often stands for CO₂ in news; monoxide has one oxygen. Quote the carbon dioxide reading in ppm, then the year. Mix-up: dioxide vs oxide with no count of oxygen; dioxide vs disaster; do not write dioxide for “air” with no formula.

Meaning

A compound of two oxygen atoms with another element, especially carbon dioxide (CO₂).

Examples

• “Quote the carbon dioxide reading in ppm, then the year, the chemistry paper said.”
• “Sulphur dioxide featured in the emissions table, which is still a named pollutant — quote mg/m³ if given.”

Good to know

carbon / sulphur dioxide; CO₂. Twin: monoxide (one oxygen). Trap: a bare “emissions” slogan with no formula. Chemistry, geography, and biology. Two oxygen atoms in the formula — name the other element and the unit.

Near in meaning

carbon dioxide, CO₂, oxide

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