The Stannides YNixSn2 (x = 0, 0.14, 0.21, 1) – Syntheses, Structure, and 119Sn Mössbauer Spectroscopy

The stannides YNixSn2 (x = 0, 0.14, 0.21, 1) were prepared by arc-melting of the pure elements. They were characterized through X-ray powder and single crystal data: ZrSi2 type, space group Cmcm, a = 438.09(6), b = 1629.6(4), c = 430.34(7) pm, wR2 = 0.0607, 386 F2 values, 14 variables for YSn2, CeNiSi2 type, Cmcm, a = 440.6(1), b = 1640.3(1), c = 433.0(1) pm, wR2 = 0.0632, 416 F2 values, 19 variables for YNi0.142(7)Sn2, a = 441.0(1), b = 1646.3(1), c = 434.6(1) pm, wR2 = 0.0491, 287 F2 values, 19 variables for YNi0.207(7)Sn2, and LuNiSn2 type, space group Pnma, a = 1599.3(3), b = 440.89(5), c = 1456.9(2) pm, wR2 = 0.0375, 1538 F2 values, 74 variables for YNiSn2. The YSn2 structure contains Sn1–Sn1 zig-zag chains (297 pm) and planar Sn2 networks (307 pm). The stannides YNi0.142(7)Sn2 and YNi0.207(7)Sn2 are nickel filled versions of YSn2. The nickel atoms have a distorted pyramidal tin coordination with Ni–Sn distances ranging from 220 to 239 pm. New stannide YNiSn2 adopts the LuNiSn2 type. The nickel and tin atoms build up a complex three-dimensional [NiSn2] network in which the yttrium atoms fill distorted pentagonal and hexagonal channels. Within the network all nickel atoms have a distorted square pyramidal tin coordination with Ni–Sn distances ranging from 247 to 276 pm. Except the Sn4 atoms which are located in a tricapped trigonal Y6 prism, all tin atoms have between 4 and 5 tin neighbors between 297 and 350 pm. 119Sn Mössbauer spectroscopic data of YNixSn2 show a decreasing isomer shift (from 2.26 to 2.11 mm/s) from YSn2 to YNiSn2, indicating decrease of the s electron density at the tin nuclei.