Structure refinement of potassium-samarium cyclotetraphosphate KSmP4O12

Single crystals of KSmP4O12 have been synthesized by a flux method. A singl e-crystal X-ray diffraction analysis characterized this structure as monocl inic with space group C2/c (No. 15) and parameters a = 7.861(1), b = 12.415 (2), c = 10.569(3) Angstrom, beta = 110.78(1)degrees, Z = 4, V = 964.4(4) A ngstrom (3), and D-x = 3.48 g.cm(-1). A full-matrix least-squares refinemen t gave R = 0.0285 for 1809 independent reflections. The atomic arrangement of the title compound can be described as a succession of layers extending along the [010] direction. P4O12 anions are centered by the planes z = 0 an d z = 1/2, whereas chains made by K+ and Sm3+ cations are centered by the p lanes z = 1/4 and z = 3/4. Samarium and potassium are surrounded by eight a nd six oxygen atoms, respectively. (C) 2000 Elsevier Science Ltd. All right s reserved.