Liu Haozhe, Tse John S, Hu Jingzhu, Liu Zhenxian, Wang Luhong, Chen Jiuhua, Weidner Don J, Meng Yue, Häusermann Daniel, Mao Ho-Kwang
HPCAT, Advanced Photon Source, Building 434E, Argonne National Laboratory, Argonne, Illinois 60439-4803, USA.
J Phys Chem B. 2005 May 12;109(18):8857-60. doi: 10.1021/jp0501594.
In-situ high-pressure synchrotron angle-dispersive X-ray diffraction for gibbsite (aluminum trihydroxide) was performed at room temperature up to 20 GPa. A pressure-induced phase transition was observed at 2.6 GPa. The new high-pressure phase can be recovered at ambient pressure. Rietveld refinement shows that the new phase of Al(OH)(3) has an orthorhombic structure, spacegroup Pbca, and the lattice parameters at ambient condition are a = 868.57(5) pm, b = 505.21(4) pm, c = 949.54(6) pm, V = 416.67(6) x 10(6) pm(3) with Z = 8. The compressibility of gibbsite and the high-pressure polymorph was analyzed, and their bulk moduli were estimated as 49.8 +/- 1.8 and 81.0 +/- 5.2 GPa, respectively. First-principles calculations of the high-pressure phase were performed to determine the hydrogen positions and to confirm the structural stability of the new phase.
在室温下至20吉帕对三水铝石（氢氧化铝）进行了原位高压同步辐射角散射X射线衍射实验。在2.6吉帕时观察到了压力诱导的相变。新的高压相在常压下可以恢复。Rietveld精修表明，Al(OH)₃的新相具有正交结构，空间群为Pbca，常压下的晶格参数为a = 868.57(5)皮米，b = 505.21(4)皮米，c = 949.54(6)皮米，V = 416.67(6)×10⁶皮米³，Z = 8。分析了三水铝石及其高压多晶型物的压缩性，估计它们的体模量分别为49.8±1.8吉帕和81.0±5.2吉帕。对高压相进行了第一性原理计算，以确定氢的位置并确认新相的结构稳定性。
