On the structural and magnetic properties of the ternary silicides Ce6M1.67Si3 (M=Co, Ni) and Ce5Ni1.85Si3

Abstract

Contrary to that reported previously, the ternary silicide ''Ce 6 Ni 2 Si 3 '' does not exist. The melting of this alloy, followed or not by annealing, leads to the existence of the two new ternary compounds, Ce 6 Ni 1.67 Si 3 and Ce 5 Ni 1.85 Si 3 . The investigation of these ternary silicides based on nickel and Ce 6 Co 1.67 Si 3 by X-ray diffraction on single crystal reveals an ordered distribution between Ni (or Co) and Si atoms. The nickel or cobalt positions in the chains of face-shared octahedra of cerium are not fully occupied with a strong delocalisation of their electron density. The structural investigations of these compounds confirm that the

Structure and magnetic properties of RNi (R=Gd, Tb, Dy, Sm) and R6M1.67Si3 (R=Ce, Gd, Tb; M=Ni, Co) hydrides

“…Crystal structure of Tb 6 Co 1.67 Si 3 D 11.2 and Ce 6 Ni 1.67 Si 3 D 12.3 According to the X-ray diffraction data, the R 6 M 1.67 Si 3 compounds have Ce 6 Ni 2 Si 3 -type hexagonal structures, space group P6 3 /m, with the unit cell parameters close to those reported previously [11][12][13][14][15]. The metal lattices of the hydride phases were of the same structure type as the virgin IMCs, but a pronounced anisotropic distortion of the unit cell was nevertheless observed: the lattice was expanded along the x and y crystallographic axes and contracted along the z axis (Table 1).…”

The new ternary silicides RE6Co1.67Si3 (RE=Ce, Nd, Gd, Tb, Dy) investigated by X-ray diffraction and magnetization measurements

“…As previously evidenced by Lemaire et al [2] and Prots' and Jeitschko [3,4] for homologous compounds Gd 6 Co 4.61 , La 6 Ni 1.54 Si 3 and Nd 6 Ni 1.66 Si 3 , these phases are non-stoichiometric and the overall formula should be written as Ce 6 Ni 2−δ Si 3 . Using X-ray powder or single crystal diffraction, an ordered distribution between Co and Si was found in Gd 6 Co 1.67 Si 3 and Ce 6 Co 1.67 Si 3 [1,5], one site being not fully occupied by Co for steric reasons. Moreover, two different kinds of environments are observed for rare earth (RE) atoms.…”

Crystal structure of lanthanum gallium antimonide, La12Ga3.26Sb24.02

“…The main feature of La 12 Ga 3.26 Sb 24.02 structure is the presence of pseudo-trigonal fragments formed by lanthanum atoms around triangular GaSb 3 planar units (figure, top). This structural units are also an inherent feature of the structure of La 13 Ga 8 Sb 21 [1] and series of hexagonal structures R 6 Ni 2 Si 3 (R = La -S m, Gd) [2][3][4][5][6][7]. Trigonal-prismatic channels formed by La atoms are outlined by corrugated Sb nets interconnected by Ga atoms.…”