SYNTHESIS OF 3-DIMENSIONAL COMPOUNDS FROM ALKALI-METAL ION-EXCHANGED GAMMA-TITANIUM PHOSPHATE

Treatment of gamma-titanium phosphate with 1 mol dm(-3) solutions of M Cl(M=Na, K, Cs)results in layered crystalline phases with compositions at 50 degrees C of: gamma-Ti(Na0.5H1.5PO4).(PO4). H2O, gamma-Ti(KHPO4 )(PO4). 1/2H(2)O and gamma-Ti(Cs0.5H1.5PO4)(PO4). 1/2H(2)O. Heating at 900 degrees C gives rise to three-dimensional crystalline compounds. The composition of the new materials depends on the type of alkali-met al present in the solid. The K phase originates KTi2(PO4)(3), the Cs p hase alpha-CsTi3P5O19, and the Na phase produces mixtures of NaTi2(PO4 )(3) and TiP2O7. Moreover, amorphous alkali-metal phosphates which are soluble in acidic media are formed. Samples of gamma-Ti(KHPO4)(PO4). 1/2H(2)O(A), KTi2(PO4)(3)(B) and alpha-CSTi3P5O19 (C) have been studie d using X-ray powder diffraction. The lattice parameters of A [a=5.063 (3) Angstrom, b=6.297(1)Angstrom, c=11.502(5) Angstrom, beta=109.30(4) degrees], B [a=8.3569(2) Angstrom, c=23.0725(3) Angstrom] and C [a=6.3 20(1) Angstrom, b=14.122(2) Angstrom, c=9.333(2) Angstrom, beta=105.82 (2)degrees] have also been calculated.