Crystal structures of nitrates of divalent hexaquocations. I. Hexaquozinc nitrate

Abstract

The crystal structure of hexaquozinc nitrate has been solved by three-dimensional methods and refined by differential syntheses. The crystals are orthorhombic, space group Pnma, with a= 12.34, b= 12"85, c= 6"29/~. The structure is composed of cations [Zn(OH~)6] z and anions NOa--. The hexaquocation has practically octahedral symmetry, with Zn-OHz = 2.097 + 0"010 A, which is very close to the values quoted in the literature. The nitrato anion has trigonal symmetry, with N-Oa,, = 1.242 + 0.009/~,, and is planar. The hexaquocations and the nitrato anions are held together by a network of hydrogen bonds, each H20 forming two hydrogen bonds with oxygen atoms of nitrato groups. Hydrogen bond lengths are in the range 2.778-2.995 A.