The crystal structure of Sb 2 Se 3 has been redetermined with 610 independent reflections, using three-dimensional intensities measured on a computer-controlled Philips PW 1100 single-crystal diffractometer. The structure does not deviate in principle from that proposed by Dönges (1950) and Tideswell, Kruse, Mc Cullough (1957), but it shows interesting details. The cell constants, obtained by least-squares calculation from direct Θ-value measurements on the diffractometer, are: α = 11.7938(9), b = 3.9858(6), c = 11.6478(7) Ä, Ζ = 4; the space group is Pnma. The positional and thermal parameters, with anisotropic temperature factors, were refined by full-matrix, least-squares calculations to a final R = 0.052. Sb 2 Se 3 is isostructural with Sb 2

The crystal structure of BiOCl has been redetermined with 3570 observed reflections of which 174 were unique measured on a computer controlled Philips PW 1100 single crystal diffractometer. The structure belongs to the tetragonal space groupThe positional and thermal parameters, with anisotropic temperature factors, were refined by full-matrix least-squares calculations to a finalEach Bi atom is eight-coordinated by 4 O and 4 Cl atoms at distances of 2.316 Å and 3.059 Å respectively thus forming a decahedron. The faces of the decahedron are 2 rectangles (O–O–O–O and Cl–Cl–Cl–Cl) with sides 3.487 Å and 8 isosceles triangles (four O–Cl–O and four Cl–O–Cl) with sides O–Cl 3.249 Å and O–O or Cl–Cl 3.487 Å.The decahedra are linked to each other by a common O–Cl edge along the

No abstract

No abstract

No abstract