Synthesis and characterization of basic bismuth(III) nitrates

The syntheses of the basic bismuth(III) nitrates [Bi6O5(OH)(3)](NO3)(5). 3H(2)O, A, [Bi6O6(OH)(3)](NO3)(3). 1.5H(2)O, B, and [Bi6O5(OH)(3)](NO3)(5). 2H(2)O, X, were investigated. A is readily obtained in hydrolysis of bismuth(III) nitrate solutions with sodium hydroxide solutions and in homogeneous hydrolysis with dilute solutions of urea. [Bi6O6(OH)(3)](NO3)(3). 1.5H(2)O is obtained in hydrothermal synthesis at 190 degrees C from Bi(NO3)(3). 5H(2)O or from [Bi6O5(OH)(3)](NO3)(5). 3H(2)O. [Bi6O5(OH)(3)](NO3)(5). 2H(2)O was obtained at 100 degrees C from an aqueous solution which was 0.74 M with respect to bismuth(III) nitrate and 1.50 M with respect to urea. The compositions of B and X were derived from thermogravimetric analysis. Indexed powder patterns are reported for B: a=3.8175(5), c=17.149(4) Angstrom for a tetragonal cell, and for X: a=15.185(1), c=15.834(2) Angstrom for a rhombohedral cell using hexagonal setting.