Structure refinement of potassium–samarium cyclotetraphosphate KSmP4O12

Single crystals of KSmP4O12 have been synthesized by a flux method. A single-crystal X-ray diffraction analysis characterized this structure as monoclinic with space group C2/c (No. 15) and parameters a = 7.861(1), b = 12.415(2), c = 10.569(3) Å, β = 110.78(1)°, Z = 4, V = 964.4(4) Å3, and Dx = 3.48 g·cm−3. A full-matrix least-squares refinement 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 and z = 1/2, whereas chains made by K+ and Sm3+ cations are centered by the planes z = 1/4 and z = 3/4. Samarium and potassium are surrounded by eight and six oxygen atoms, respectively.