Preparation of Cr₅Si₃, CrSi and CrSi₂ Single Crystals in Molten Tin

Abstract

The single crystals of Cr₅Si₃, CrSi and CrSi₂ were prepared by the reaction between elementary chromium and silicon in molten tin under an argon atmosphere.
The conditions for the preparation are as follows: temperature of molten tin, 1400°C; reaction time, 10 h; mixing atomic ratios of raw materials, Si/Cr =- O.6 and Sn/Cr =6.4 for Cr₅Si₃, Si/Cr=1.0 and Sn/Cr =6.4 for CrSi, and Si/Cr=2.0 and Sn/Cr=6.4 for CrSi₂. Under these conditions, the Cr₅Si₃ single crystals of polyhedral shape and of needle shape extending to‹100› direction, the CrSi single crystal of polyhedral shape and the CrSi₂ single crystal of hexagonal prismatic shape extending to ‹0001› direction were obtained as a single phase, respectively. Each crystal exhibited grayish metallic appearance. Lattice constants measured are as follows: c₀=9, 155± O.002Å and ao=4.636+ 0.003Å for Cr₅Si₃, a₀ =4.626±0.002Å for CrSi, and c₀ =4.426 ± 0.002Å and c₀=6.375± 0.002Å for CrSi₂.