Additional compounds with a relation to the α-Ba2ScAlO5-type: Ba6Rh2.33Yb2Al1.67 O15, Ba5.5Ca0.5Rh2Y2Al2O15 and Ba6Rh4Al2O15

Single crystals of the compounds Ba6Rh2,33Yb2Al1,67O15 (I), Ba5,5Ca0,5Rh2Y2Al2O15 (II) and Ba6Rh4Al2O15 (III) were prepared by flux technique. X-ray work shows 6L-Perovskite structure and relationships to α-Ba2ScAlO5. They crystallize in the space group D3h1-P6¯m2; I: a 5.854, c 14.660 angstroms; II: a 5.859, c 14.691 angstroms; III: a 5.865, c 14.626 angstroms, Z = 1. The crystal structures are characterized by Rh2O9 and Al2O9 double octahedra and in example III by single RhO6 octahedra in positions of the LnO6 octahedra.