Search

International audience; Na2 Cd(OH)4 is an intermediate product of great interest in the formation of Cd(OH)2 gamma , which is composing the active anodic material of discharged nickel-cadmium batteries. Synthesis and study of Na2 Cd(OH)4 were caried out. Unit-cell parameters have been determined from the X-ray diffraction powder pattern. The structure is deriving from the NaCl type. The symmetry is orthorhombique. a(Å) = 10.339 (8) ; b(Å) = 10.572 (9) ; c(Å) = 9.440 (8) ; z = 8 ; ρ (calc.) = 2.91 g.cm-3 MATERIALS INDEX : hydroxy-cadmiates, sodium.

Copyright © International Union of Crystallography; C21H34N3O5+.Cl-, Mr = 444.0, orthorhombic, P212121, a = 26.074 (5), b = 17.591 (4), c = 5.224 (2) Å, V = 2396.1 (10) ų, Z = 4, Cu Kα, λ = 1.5418 Å, µ = 1.71 mm-1, F(000) = 952, Dx = 1.231 Mg m-3, room temperature, final R = 0.080 and wR = 0.070 for all 2439 reflections [(sinθ)/λ > 0.03 Å-1]. The peptide groups are planar; torsion angles (-101 and -88°) indicate a roughly helical structure. The peptide bonds have a trans conformation. The crystal structure is stabilized by a network of hydrogen bonds.

The authors have studied the evolution with the temperature of the structure of new Ca x WO 3 and Al x WO 3 tungsten bronzes in the homogeneity range corresponding to small calcium and aluminium concentrations. The rate of the inserted elements and the increasing of the temperature have concording action on the stability of the obtained monoclinic, orthorhombic and tetragonal phases. The authors have considered the influence of the electronic and steric factors upon the stability of the various structures.