Intermetallics La11Ru2Al6 and Ce11Ru2Al6 with a new structure type

 

Chem. Met. Alloys 3 (2010) 101-107

 

E.V. MURASHOVA, A.I. TURSINA, Zh.M. KURENBAEVA, H. NOËL, Y.D. SEROPEGIN

 

The crystal structures of RE11Ru2Al6 (RE = La, Ce) were determined from single-crystal X-ray diffraction at room temperature. The compounds are isostructural and belong to a new structural type: orthorhombic space group Pbam, Z = 2, a = 14.619(2), 14.0799(14) Å, b = 15.705(3), 15.4879(16) Å, = 4.4866(7), 4.4685(4) Å, respectively, Pearson symbol oP38. An interesting feature of the Ce11Ru2Al6 structure is the formation of short Ce-Ru distances of 2.4404(8) Å in one of the six crystallographically independent Ce‑polyhedra, whereas in the La11Ru2Al6 structure the La-Ru distances are only slightly shorter than the sum of the covalent radii of La and Ru (2.7033(8) Å).

 

Near-neighbor coordination of the Ru1 atoms in a) La11Ru2Al6; b) Ce11Ru2Al6.

 

Keywords

Rare-earth intermetallics / Crystal structure / Crystal chemistry of intermetallics