Crystal structure of trisodium phosphonoformate hexahydrate, Na3PO3CO2,6H2O

Abstract

The structure of trisodium phosphonoformate hexahydrate, Na₃PO₃CO₂,6H₂O, has been determined simultaneously and independently in two laboratories. One analysis used 2238 visually estimated X-ray reflexions and was refined to R 10·68%. The other used 1550 intensities measured with a microdensitometer and was refined to R 12·7%. In general the two sets of derived atomic co-ordinates agree well, though there are one or two exceptions.

The structure consists of sodium ions surrounded octahedrally by six oxygen atoms, some from water molecules and some from the phosphonoformate ions. The octahedra share one edge such that chains of octahedra run parallel to [a] and are held together by an intricate net-work of hydrogen bonds. The P–C bond is long (1·872 and 1·865, mean 1·869 Å), and the lengthening is ascribed to repulsion between negative charges on the phosphonoformate ion.