Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, Higashi-Hiroshima 739-8527, Japan.
Inorg Chem. 2013 May 20;52(10):6039-45. doi: 10.1021/ic400395n. Epub 2013 May 8.
The Zintl compound CaAl2Si2 peritectically decomposes to a new ternary cubic Laves phase Ca(Al,Si)2 and an Al-Si eutectic at temperatures above 750 °C under a pressure of 13 GPa. The ternary Laves phase compound can also be prepared as solid solutions Ca(Al(1-x)Si(x))2 (0.35 ≤ x ≤ 0.75) directly from the ternary mixtures under high-pressure and high-temperature conditions. The cubic Laves phase structure can be regarded as a type of clathrate compound composed of face-sharing truncated tetrahedral cages with Ca atoms at the center, Ca@(Al,Si)12. The compound with a stoichiometric composition CaAlSi exhibits superconductivity with a transition temperature of 2.6 K. This is the first superconducting Laves phase compound composed solely of commonly found elements.
在 13GPa 的压力下，Zintl 化合物 CaAl2Si2 在高于 750°C 的温度下会发生包晶分解，形成新的三元立方 Laves 相 Ca(Al,Si)2 和 Al-Si 共晶。在高压高温条件下，三元 Laves 相化合物也可以直接由三元混合物制备为固溶体 Ca(Al(1-x)Si(x))2（0.35≤x≤0.75）。立方 Laves 相结构可以看作是一种由面共享截角四面体笼组成的笼型化合物，其中 Ca 原子位于中心，Ca@(Al,Si)12。具有化学计量组成 CaAlSi 的化合物表现出超导性，其转变温度为 2.6K。这是第一个由常见元素组成的超导 Laves 相化合物。
