The crystal structure of tin(II) bis(dihydrogenphosphate)

Abstract

The crystal structure of Sn[H₂PO₄]₂ has been determined from X-ray diffractometer data by Patterson and Fourier methods. Crystals are monoclinic, space group C2/c, with Z= 4 in a unit cell of dimensions a= 16.561 (9), b= 6.896(2), c= 5.939(2)Å, and β= 91.35(4)°. The structure has been refined by least-squares methods to R 0.039 for 1 429 reflections. It consists of [H₂PO₄]^– tetrahedra and Sn²⁺ ions. Each Sn atom has four O neighbours all lying on one side. Two of the Sn–O bonds are short (2.209 Å) and two are longer (2.466 Å). Such a co-ordin-ation of Sn is usually described as distorted square pyramidal, with four basal oxygens and the apex occupied by a stereochemically active lone pair of electrons from Sn. The [H₂PO₄]^– groups are linked by strong hydrogen bonds (2.545 and 2.627 Å).