sulphur trioxide

British  

noun

1. Systematic name: sulphur(VI) oxide.  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

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Example Sentences

Saturated hydrocarbons do not react with sulphur trioxide, but unsaturated hydrocarbons are readily attacked by SO_3.

From Synthetic Tannins by Grasser, Georg

The product of this reaction is sulphuric acid, so that sulphur trioxide is the anhydride of that acid: SO3 + H2O = H2SO4.

From An Elementary Study of Chemistry by McPherson, William

The acid commonly used is made by the "contact" process, in which sulphur dioxide is oxidized to sulphur trioxide, and then, with the addition of water, changed to sulphuric acid.

From The Automobile Storage Battery Its Care And Repair by Witte, Otto A.

SO2 is called sulphur dioxide, to distinguish it from SO3, sulphur trioxide.

From An Introduction to Chemical Science by Williams, Rufus Phillips

The olefines—ethylene, &c.—are generally absorbed by a very strong sulphuric acid prepared by adding sulphur trioxide to sulphuric acid to form a mixture which solidifies when slightly cooled.

From Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 4 "G" to "Gaskell, Elizabeth" by Various