Rietveld refinement of the crystal structures of hexagonal Y6Cr4+xAl43−x (x=2.57) and tetragonal YCr4−xAl8+x (x=1.22)

Y6Cr4+xAl43−x (x = 2.57); space group P63/mcm, a = 10.8601(1) Å, c = 17.6783(3) Å, V= 1805.7(1) Å3, Z=2; isostructural to Yb6Cr4+xAl43−x, (x=1.76) with two aluminium sites partially occupied by chromium (44% and 27% Cr). YCr4−xAl8+x (x=1.22); space group I4/mmm, a = 9.0299(2) Å, c = 5.1208(2) Å, V=417.55(3) Å3, Z=2, disordered variant of CeMn4Al8 with one chromium site (8f) partially occupied by aluminium (33% Al); X-ray powder diffraction data were collected on a well-crystallized multiphase sample containing 43 wt.% of Y6Cr4+xAl43−x, 27 wt.% of Y2Cr8−xAl16+x, 16 wt.% of Al, 13 wt.% of YAl3, and traces of Y2O3. Structure refinement converged at Rwp = 2.0% and RB = 3.5, 3.6% resp. for a total of 78 parameters and 1190 reflection

Nd₁₁Pd₄In₉ compound – A new member of the homological series based on AlB₂ and CsCl types

The Nd11Pd4In9 compound was prepared by arc melting of pure metals under an argon atmosphere. Crystal structure was refined from X-ray single crystal diffractometer data (space group Cmmm, a = 14.843(3), b = 22.284(3), c = 3.7857(6) Å, Z = 2, RI = 0.0584, 653 F2 values). It has own structure type and together with Mn2AlB2, Cr3AlB4, Mo2FeB2 and Lu5Ni2In4 structure types belongs to homological series based on AlB2 and CsCl structure types with common formula Rm+nM2nXm