ИСТИНА

Intermetallics La9Ru4In5 and Ce9Ru4Ga5 were synthesized by arc melting of the elemental components with subsequent annealing at 600ºC. The crystal structures were determined from X-ray single-crystal diffraction data. The new intermetallics Ce9Ru4Ga5 and La9Ru4In5 belong to one structural family, crystallize in tetragonal system, Pearson symbol tI36, and present new structural types. Intermetallic Ce9Ru4Ga5 crystallizes in non-centrosymmetric space group I4mm, Z = 2, a = 10.1132(4), c = 8.1212(3) Å. La9Ru4In5 compound crystallizes in centrosymmetric space group I4/mmm, Z = 2, a = 10.604(3), c = 8.535(5) Å. The short Ce–Ru distance of 2.366 Å is an interesting feature of the Ce9Ru4Ga5 structure; this phenomenon is caused by intermediate valence state of cerium atoms. The experimental L3-Ce XANES spectroscopy data show that the average valence of cerium in intermetallic Ce9Ru4Ga5 is about ~3.10 at 7ºC.