Crystal structure of disodium orthophosphite pentahydrate

Abstract

Na₂HPO₃,5H₂O crystallises in the orthorhombic system. The space group is Pmn2₁ with a= 7·17, b= 6·36, and c= 9·07 Å, Z= 2. The structure has been refined by a three-dimensional least-squares method using 700 reflections to R 0·075. The water molecules link adjacent tetrahedral phosphite ions which lie on mirror planes of symmetry to form a three-dimensional hydrogen-bonded network. The phosphite ion has one P–O distance (1·48 Å) considerably shorter than the other two (1·52 Å).