Al(OH)_3微观晶体结构、热稳定性及成键特性的理论计算

Theoretical Calculations on Microscopic Crystal Structure,Thermal Stability and Bonding Characteristics of Al(OH)_3

采用第一性原理计算方法,研究了α-Al(OH)3的微观晶体结构、热稳定性及成键特性。结果表明:α-Al(OH)3呈单斜晶体结构,计算所得的晶胞参数、原子坐标与实验值吻合;分解反应热的计算表明α-Al(OH)3具有较高的热力学稳定性;电子结构分析发现α-Al(OH)3呈绝缘体性质,在其晶体内部,Al与OH间呈离子键作用,O-H间呈混合的共价-离子键作用,且O(2s)(2p)与H(1s)轨道电子间的成键作用主宰着α-Al(OH)3晶体的热力学稳定性。

Using first-principles calculations method, the crystal structure, thermal stability and bonding characteristics of α-Al（OH）3 fire retardant were systematically investigated. The results show that α-Al（OH）3 has monoclinic crystal structure, and the calculated cell parameters and atomic coordinates are in good agreement with experimental values. The calculated decomposition reaction heat shows that α-Al（OH）3 presents high thermal stability and good fire-retarding performance. Analysis of electronic structures shows that α-Al（OH）3 exhibits the insulative cha- racteristic. Within α-Al（OH）3 crystal, there are ionic bonding interactions between Al and OH unit, while there are mixed covalent-ionic bonding interactions between O and H. The thermal stability of α-Al（OH）3 is depended on the bonding interactions of O（2s）（2p） and H（ls） orbital electrons.