The synthesis and characterization of lanthanum phosphite phenylphosphonate mixed derivatives

Abstract

Mixed derivatives of general formula La 2(O 3PH) 3− x (O 3PC 6H 5) x · yH 2O have been synthesized from both aqueous and ethanolic solutions. The mixed derivatives are single phase layered compounds made up of randomly dispersed phosphite and phenylphosphonate groups throughout the layer, as determined by X-ray powder diffraction, IR, TGA and 31P MAS NMR. Two representative mixed derivatives prepared in aqueous media, La 2(O 3PH) 1.75(O 3PC 6H 5) 1.25·2.3H 2HO and La 2(O 3PH) 2.36(O 3PC 6H 5) 0.64·1.9H 2O, and one mixed derivative formed from ethanol solution, La 2(O 3PH) 2.45(O 3PC 6H 5) 0.55·2.7H 2O, are described in detail. The aqueous phase mixed derivatives have interlayer spacings ( d) equivalent to phenyl-phenyl abutments (∼15 Å), whereas the phase formed in ethanol has a d-spacing consistent with a phosphite-phenyl abutment (∼11 Å). The factors involved in preparing mixed derivatives are discussed.