Tin(IV) phosphonates with α-layered structure: synthesis and characterization

Abstract

The synthesis of layered compounds of the general formula Sn(RPO₃)₂·xH₂O (R = phenyl, 2-carboxyethyl) and Sn(ROPO₃)₂·xH₂O (R = dodecyl) are reported. These compounds are formed by the reaction of nitric solutions of SnCl₄ with the phosphonic acid or phosphoric ester followed by heating under reflux. The interlayer distances of 13.87, 15.37 and 32.70 Å for 2-carboxyethyl, phenyl and dodecyl derivatives, respectively, are determined by the XRD patterns. A linear relationship between the molar volume and the interlayer distance is observed suggesting an alpha structure similar to α-Sn(HPO₄)₂·H₂O. FTIR spectra show the formation of an Sn—O—P skeleton.