Ternary Stannides Li<i>T</i>Sn₄ (<i>T</i> = Ru, Rh, Ir)Chemical Bonding and Physical Properties

Abstract

Pure samples of the ternary stannides LiTSn4 (T = Ru, Rh, Ir) have been synthesized from the elements in sealed tantalum tubes. They crystallize with an ordered version of the PdGa5 type. LiTSn4 (T = Ru, Rh, Ir) are all metallic conductors and Pauli paramagnets. Spectroscopic measurements indicate significant differences in the chemical bonding properties: As revealed by both 119Sn Mössbauer spectroscopy and solid-state NMR data, the local electron distribution at the tin site is more anisotropic in LiRuSn4 compared to the other two materials. In addition, 7Li Knight shift and spin-lattice relaxation times indicate that LiRuSn4 has a much higher electron density at the lithium atom arising from conduction electrons at the Fermi level. These findings are in good agreement with the results of DFT band structure calculations.