Synthesis and characterisation of new layered mixed metal phosphonate materials magnesium-zinc phosphonates Mg₁₋xZnx(O₃PR). H₂O and nickel-zinc phosphonates Ni₁₋xZnx(O₃PR).H₂O using mixed divalent magnesium-zinc and nickel-zinc hydroxides

Layered mixed divalent metal phosphonates Mg1-xZnx(O3PR).H2O [with R = CH3,C2H3, C6H5] and Ni1-xZnx(O3PR).H2O [with R = CH3, C2H3, C6H5, (CH2)(2)COOH] have been prepared by heating, respectively, mixed divalent magnesium-zinc hydroxides and nickel-zinc hydroxides above the melting point of the phosphonic acid being used. A range of pre-formed mixed divalent metal hydroxides Mg1-xZnx(OH)(2) and Ni1-xZnx(OH)(2) with different ratios of Zn content (x = 0, 0.1, 0.25, 0.5) are obtained by isomorphous substitution of zinc into the, respective, Mg(OH)(2) and Ni(OH)(2) brucite-type structure: space group P (3) over bar m1; a = 3.13-3.15 Angstrom, c = 4.63-4.77 Angstrom). The phosphonate materials have been characterized by X-ray powder diffraction, IR, TGA, and P-31 MAS NMR. Mg1-xZnx(O3PR).H2O and Ni1-x Zn-x(O3PR).H2O crystallize in an orthorhombic system with space group Pmn2(1) with b = 5.55-5.69 Angstrom, c = 4.71-4.86 Angstrom and a varying according to the size of the organic group R.