The high-pressure behaviour of the "moganite" polymorph of SiO2
The high-pressure behaviour of the "moganite" polymorph of SiO2
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DOI：
10.1127/0935-1221/01/0013-0351
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发表时间：
2001-03-01
影响因子：
2.1
通讯作者：
Chateau, C
中科院分区：
文献类型：
--
作者：
Léger, JM;Haines, J;Chateau, C
采用角色散x射线粉末衍射技术，研究了室温下二氧化硅“莫干石”多晶的高压行为。根据P-V数据计算体积模量：石英的B′(0)固定为5.2,B′(0)= 32.2 (3)GPa。在5 GPa以上，莫干石的摩尔体积小于石英的摩尔体积。压力诱导非晶化逐渐发生；GPa在25分以上。减压后，最大压力在25-30 GPa以下时，非晶化是部分可逆的，压力在45 GPa以上时，非晶化是不可逆的。二氧化硅和氮化氧磷PON（二氧化硅类似物）的石英和莫干石多晶的压力诱导非晶化与四面体的扭曲有关，并且在二氧化硅的情况下，与存在更致密的相有关，其中阳离子具有更高的配位数。
The high-pressure behaviour of the "moganite" polymorph of SiO2 has been investigated by angle-dispersive, X-ray powder diffraction in a diamond anvil cell at room temperature. The bulk modulus was calculated from the P-V data: B-0 = 32.2 (3) GPa with B'(0) fixed to 5.2 as for quartz. The molar volume of moganite becomes lower than the volume of quartz above 5 GPa. Pressure-induced amorphisation occurred progressively; it was complete above 25 GPa. Upon decompression, amorphisation was partially reversible if the maximum pressure reached was below 25-30 GPa and irreversible when the pressure reached was above 45 GPa. The pressure-induced amorphisation of the quartz and moganite polymorphs of silica and phosphorus oxynitride PON, a silica analogue, is related to the distortion of the tetrahedra and, in the case of silica, to the presence of a much denser phase, in which the cation has a higher coordination number.