Crystal Chemistry of the Hydrogen Selenites MH2n+1(SeO3)n+1

Abstract

Thirty six SeO3 formations in 17 crystal structures of selenites with formula MH2n+1(SeO3)n+1 , where M = H, Li, Na, K, Rb, Cs, NH4, Tl and n = 0-3 were analysed in this paper. There are found five types of selenites: SeO(OH)2 (n = 14), SeO2(OH)- (n = 17), SeO(OH0.5)2-(n = 1), Se(OH0.5)30.5-(n = 3) and SeO(OH)(OH0.5)0.5- (n = 1). All formations SeO3 have the point symmetry 1. The overall mean value of 108 individual Se-O distances is 1.70(5) Å, of 108 O-Se-O angles is 101(3) grad. and of 57 O...O distances in hydrogen bonds is 2.60(6) Å. A very significant correlation was found between the ionic radius r (Å) of the element M and the value V/Z (Å3).