Powder diffraction refinement of theCo₂Al₅structure

Abstract

The structure of Co 2 Al 5 (hP28, Pb^lmmc) was refined by means of Rietveld method. The shortest Co-Al distance amounts 2.338 A. Co 2 Al 5 shows a homogeneity range between Co 2 9Al 71 and Co 275 Al 725 at 1125 K. The concentration dependence of lattice parameters was also measured. The axial ratio cla increases with increasing mole fraction of aluminum. © 1998 International Centre for Diffraction Data. [S0885-7156(98)00701-5]

Preparation and structure refinements of Pd2Mg5 and Ir2.096Mg1.980In2.924 with hexagonal Co2Al5 type structure

“…Analysis of both data sets were compatible with space group P6 3 /mmc in agreement with all previous investigations [2][3][4][5][6][7][8][9][10][11]. The atomic parameters of Co 2 Al 5 [2] were taken as the starting positions and both structures were refined with SHELXL-97 [24] (full-matrix least-squares on F 2 ) with anisotropic displacement parameters for all atoms.…”

“…Co 2 Al 5 [2][3][4], Rh 2 Al 5 [5], FeNiAl 5 [6], Cu 3 Cd 10 [7], Pd 2 Mg 5 and Rh 2 Mg 5 [8,9], Ir 2 Mg 5 [10], and the gallides Sc 27 Co 5 Ga 5 and Sc 27 Ni 5 Ga 5 [11]. Among these intermetallics, Co 2 Al 5 has most intensively been investigated with respect to chemical bonding [12,13], corrosion resistant coatings [14] or various composite materials.…”

The Fe–Ni–Al phase diagram in the Al-rich (>50at.% Al) corner

“…For Fe 4Àx Ni x Al 10 (t1) the Co 2 Al 5 -structure type [20] as proposed in Refs. [9,10] was confirmed.…”

Crystal structures of cobalt aluminum silicide, Co19+xAl43+ySi12-y (x = -0.14, y = 0.14; x = 0.49, y = -0.49), the ϒ phase in the Co-Al-Si system

“…At 800°C it is in equilibrium with the adjacent binary compounds CoAl 3 and Co2Al9, with the ternary phases d, j and c and with liquid phase [1]. It adopts an own structure type with no obvious structural relations to the adjacent phases in the binary system [2][3][4][5][6]. Important common structural motifs of these compounds, like the existence of condensed pentagonal prismatic channels [7] or the existence of a ²cluster² formed by two trigonal prisms around cobalt and a distorted rectangular prism around aluminum [8] are not found in the title compound.…”