A structural investigation of praseodymium potassium hexacyanoferrate (II) tetrahydrate, PrKFe(CN)6 · 4H2O

Abstract Single-crystal and powder X-ray diffraction data, thermal gravimetric analysis, and infrared spectral data are present for PrKFe(CN) 6 · 4H 2 O. The crystal structure has been determined by single-crystal diffractometry and refined by the least-squares method to yield R = 0.0149 and R w = 0.0155. The praseodymium ions are linked nonlinearly to the FeC 6 octahedra by cyanide bridges. Cavities within the structure are occupied by potassium ions and zeolitic water molecules which are within hydrogen bonding distance to the water molecules which are bonded to the nine-coordinated praseodymium ions, PrN 6 (H 2 O) 3 . The powder diffraction data obtained by employing a Siemens Debye-Scherrer camera have yielded cell parameters of a = 7.374(2) and c = 13.816(3)A. The compound is hexagonal, P6 3 m (No. 176), D M = 2.34(3) Mg m −3 , and D X = 2.368 Mg m −3 . The powder diffraction data have been evaluated and the resultant quantitative figures of merit are F 30 = 30(0.021, 48) and M 20 = 29.7. Important bond lengths are: PrN = 2.540(3); FeC = 1.908(3); PrO = 2.704(4); and CN = 1.159(4) A.