Sesquioxide
Sesquioxides are chemical compounds , more precisely oxides , which have a ratio of metal or semi-metal to oxygen of 1: 1.5 ( sesqui = "one and a half times ").
Sesquioxides with a stoichiometrically precise composition therefore have the general empirical formula A 2 O 3 , where A has the oxidation number + III. Sesquioxides mostly form crystalline solids.
Examples of metal sesquioxides:
- Iron (III) oxide Fe 2 O 3 : Iron sesquioxide, in nature as a mineral hematite
- Aluminum oxide Al 2 O 3 : aluminum sesquioxide, naturally the mineral corundum
- the oxides of the trivalent rare earth metals
In naturally grown soils, iron (III) oxide, manganese (III) oxide and aluminum oxide are particularly important. The term sesquioxide therefore also stands for these three compounds in soil science .
Examples of semi-metal sesquioxides:
- Boron trioxide B 2 O 3 (boron sesquioxide)
- Arsenic (III) oxide As 2 O 3 (arsenic sesquioxide)
Sesquioxide in the 1st main group :
- Rb 4 O 6 → [(Rb + ) 4 (O 2 2− ) (O 2 - ) 2 ]
Individual evidence
- ↑ Norman N. Greenwood, A. Earnshaw: Chemistry of the Elements . 2nd Edition, Butterworth-Heinemann, Oxford 1997, ISBN 0-7506-3365-4 .