Vitreous forsterite (Mg2SiO4):: Synthesis, structure, and thermochemistry
Vitreous forsterite (Mg2SiO4):: Synthesis, structure, and thermochemistry
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DOI：
10.1029/2000gl012222
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发表时间：
2001-07-01
影响因子：
5.2
通讯作者：
Key, TS
中科院分区：
文献类型：
--
作者：
Tangeman, JA;Phillips, BL;Key, TS
在这里，我们报道了镁橄榄石(Mg2SiO4)组成玻璃的首次合成，作为一种基本物相纯的块体材料。在无容器条件下，非均质成核点最少，玻璃是在700K/S的氧气中冷却约1 mm的液态镁硅氧滴形成的。Si-29核磁共振谱数据表明，玻璃中的SiO_4四面体和MgO_6八面体以角共用的方式排列，但在晶化后多面体单元重组形成边共享的键。置换温降量热法测得玻璃的热值比晶体的热值高61.4+/-1.3kJ/mol。
Here we report the first synthesis of a forsterite (Mg2SiO4) composition glass as an essentially phase-pure bulk material. Under containerless conditions, with heterogeneous nucleation sites minimized, glass forms by cooling ca. 1 mm liquid Mg2SiO4 droplets in oxygen at 700 K/s. Si-29 NMR spectroscopic data indicate that the SiO4 tetrahedra and MgO6 octahedra exist in a corner sharing arrangement in the glass, but upon crystallization the polyhedral units reorganize to form edge-sharing linkages. Transposed temperature drop calorimetry shows that the glass is 61.4 +/- 1.3 kJ/mol higher in enthalpy than the crystal.