Synthesis and characterization of new oxide hydrates H-x(VxMo1-x)O-3 center dot 0.3H(2)O and H-0.27(V0.27W0.73)O-3 center dot 1/3H(2)O

From acid solutions obtained by dissolution of molybdenum or tungsten metal and V2O5 in hydrogen peroxide solution, pure and well-crystallized phases have been prepared under the general formula HxVxMo1-xO3 . 0.3H(2)O (0.06 less than or equal to x less than or equal to 0.18) and H0.27V0.27W0.73O3 . 1/3H(2)O. The former presents an hexagonal structure (for instance, when x = 0.13, a = 10.6129(5) Angstrom, c = 3.7045(3) Angstrom, and space group P6(3)) and the latter is isostructural with orthorhombic WO3 . 1/3H(2)O (a = 7.272(1) Angstrom, b = 12.573(2) Angstrom, c = 7.728(1) Angstrom, and space group Fmm2). These phases have been characterized by classic solid state techniques and their thermal behavior has also been studied. (C) 1996 Academic Press, Inc.