TIN(IV) PHOSPHONATES WITH ALPHA-LAYERED STRUCTURES - SYNTHESIS AND CHARACTERIZATION

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 angstrom 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 alpha-Sn(HPO4)2.H2O. FTIR spectra show the formation of an Sn-O-P skeleton.