[2] The hydrated oxide is prepared by hydrolysis of antimony pentachloride; or by acidification of potassium hexahydroxoantimonate(V).
[4][5] It is also used as an ion exchange resin for a number of cations in acidic solution including Na+ (especially for their selective retentions), and as a polymerization and oxidation catalyst.
Heating to 900 °C (1,650 °F) produces a white, insoluble powder of Sb2O4 in both α and β forms.
The β form consists of antimony(V) in octahedral interstices and pyramidal SbIIIO4 units.
The pentoxide can be reduced to antimony metal by heating with hydrogen or potassium cyanide.