sulphur trioxide

noun

a white corrosive substance existing in three crystalline forms of which the stable ( alpha- ) form is usually obtained as silky needles. It is produced by the oxidation of sulphur dioxide, and is used in the sulphonation of organic compounds. Formula: SO 3 Systematic namesulphur(VI) oxide

Sulphur trioxide forms thin needle-shaped crystals, arranged in feathery groups.

Sulphur trioxide is a colorless liquid, which solidifies at about 15° and boils at 46°.

Small quantities of sulphur trioxide (SO3) may also be formed in the combustion of sulphur.

Sulphur trioxide is formed, and as it issues from the tube it is absorbed in water or dilute sulphuric acid.

Such oxides as sulphur trioxide, nitrogen pentoxide, etc., do not possess acid properties except in combination with water.

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