A number of new isostructural ternary intermetallides of the composition R4Ru2Ga3 (R = Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er) have been discovered in R–Ru–Ga ternary systems. X-ray examination of the Nd4Ru2Ga3 single crystal showed that this compound crystallizes in the monoclinic system and is a representative of a new structural type: a = 10.899(3), b = 4.0533(11), c = 9.720(3) Å, β = 111.080(7)°, C2, Z = 2, R1 = 0.043, wR2 = 0.077 for 1518 reflections. A feature of the structure is the presence of distorted fragments of RuNd6 (type AlB2) and GaNd8 (type CsCl) in it. The minimum Nd–Ru distance in a polyhedron is 2.8463(16) Å, which is significantly shorter than the sum of their atomic radii. The parameters and volumes of the elementary cells in the R4Ru2Ga3 series (R = Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er) decrease in accordance with lanthanide compression, and the melting temperatures increase.
Read full abstract