Affinement par diffraction neutronique du bis(dihydrogénopyrophosphate) tripotassique et monosodique

Abstract

Abstract. K3Na(H2P207) 2, monoclinic, C2/c, Z = 4, a = 16.912(8), b = 7.251 (5), e --11.015 (6) A, fl= 100.25 (5)°: three-dimensional single-crystal neutron diffraction. A full-matrix least-squares refinement based on F gave a final R value of 0.029. The structure contains a normal hydrogen bond and two symmetryrestricted hydrogen bonds of lengths 2.531 (3) and 2.500 (3)A. These contacts lie respectively on a twofold axis and an inversion centre. The hydrogen atom H(2) is.disordered over two sites, separated by 0.62 A; H(3) is located at the centre of symmetry with large thermal motion along the hydrogen bond.

Synthesis and crystal structure of Na5Cu3(PO4)2(PO4HPO4)

“…Further Ο atoms have Cu(2) -Ο > 3.011 Ä, and again they are excluded from the coordination figure. in K 3 Na(H 2 P20 7 )2 Dumas et al (1980) found a symmetric hydrogen bond as well as a Η atom which is disordered over two separate sites restricted by a twofold axis, and in CaHP0 4 (Catti et al, 1980) a hydrogen bond was found having at room temperature statistically the symmetry T, but at lower temperatures an ordering of the Η atom could be decided. six) Cu -Ο bonds < 2.20 Ä have seldom been found in inorganic crystal structures: e.g.…”

Hydrothermal synthesis, crystal structure, and vibrational and Mössbauer spectra of a new tricationic orthophosphate — KCo3Fe(PO4)3

“…Atomic coordinates and isotropic thermal parameters are given in Table 3 and selected interatomic distances in Table 4. The Co atoms are arranged in five-vertex polyhedra, like distorted squarebased pyramids for both the Co(1) and Co (2) (27)), forms more complex polyhedra with the distortion indices being extremely variable, ranging from 0.080 up to 0.199 (28)(29)(30). As can be seen from Fig.…”