Crystal structure, interatomic distances, and X-ray spectra of the compounds RM2Si2, R2M3Si5, and RMSi3 (R = rare earth, M = transition metal)

It was shown by analyzing the average interatomic distances in RM2Si2, R2M3Si5, and RMSi3 (R = Sc, Y, Ln; M = transition metal) that the M-Si bonds in these ternary compounds are predominantly covalent and the R-Si and M-R bonds are predominantly metallic. YNi2Si2 and YNiSi3 were studied by x-ray emission spectroscopy. The total and partial densities of states in YNi2Si2 were calculated by the linearized muffin-tin-orbital method. The Ni-Si bonds in YNiSi3 are of more covalent character than those in R2Ni3Si5, and the Si-Si bonds in YNiSi3 are of more covalent character than those in YNi2Si2 and R2Ni3Si5.