(1. 中南大學(xué) 粉末冶金國家重點實驗室，長沙 410083;
2. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083)
摘 要: 根據(jù)固體與分子經(jīng)驗電子理論，通過鍵距差(BLD)方法，計算了金屬間化合物MoSi2的價電子結(jié)構(gòu)和理論結(jié)合能。結(jié)果表明，MoSi2理論結(jié)合能為1 677.1 kJ/mol，與實驗值吻合。由于Si原子偏移，沿〈001〉方向分布的Si—Si原子鍵共價電子數(shù)最多，nD=0.402 04。MoSi2晶體中含有較高密度的晶格電子，使MoSi2具有良好的導(dǎo)電性。MoSi2晶體中鍵絡(luò)分布不均勻性是導(dǎo)致晶體脆性的主要原因。
關(guān)鍵字: 二硅化鉬；價電子；結(jié)合能；脆性
cohesive energy calculation of MoSi2
（1. State Key Laboratory of Powder Metallurgy, Central South University,Changsha 410083, China;
2. School of Materials Science and Engineering, Central South University,Changsha 410083, China）
Abstract:According to the empirical electron theory of solid and molecule, the valence electron structure and theoretical cohesive energy of MoSi2 were calculated by the BLD method. The results show that the theoretical cohesive energy of MoSi2 is 1 677.1 kJ/mol, which agrees well with the experimental data. Because of a shift in Si positions, the valence electrons between Si—Si atoms along <001> direction are the most (nD = 0.402 04). There are lattice electrons with higher densities in MoSi2, which accounts for the good conductivity of MoSi2. Also, it is speculated that the brittleness of MoSi2 can be explained primarily by a heterogeneity of bond distribution.
Key words: molybdenum disilicide; valence electron; cohesive energy; brittleness
