REFINEMENT OF THE STRUCTURE OF SI2N2O

Silicon nitride oxide, M(r) = 100.18, orthorhombic, Cmc2(1), Z = 4, lambda(Cu K-alpha) = 1.54178 angstrom, a = 8.8717 (6), b = 5.4909 (16), c = 4.8504 (7) angstrom, V = 236.28 (12) angstrom 3, D(x) = 2.816 g cm-3, mu = 114 cm-1, F(000) = 200, R = 0.0222 for 24 parameters and 192 unique observed reflections at T = 296 K and a = 8.8742 (10), b = 5.4894 (15), c = 4.8464 (14) angstrom, V = 236.09 (16) angstrom 3, D(x) = 2.818 g cm-3, mu = 114 cm-1, F(000) = 200, R = 0.0205 for 24 parameters and 136 unique observed reflections at T = 123 K. The crystal structure of Si2N2O has been refined from X-ray diffraction data obtained by a rotating anode X-ray source. Our results confirm the structure determined by earlier X-ray work [Idrestedt & Brosset (1964). Acta Chem. Scand. 18, 1879-1886] and provide an improved precision in the determination of the atomic coordinates. The influence of temperature on coordinates and temperature factors is negligible.