Glass Formation at the Limit of Insufficient Network Formers
Glass Formation at the Limit of Insufficient Network Formers
复制标题
网络形成剂不足的极限下的玻璃形成
DOI：
10.1126/science.1095047
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发表时间：
2004
期刊：
影响因子：
56.9
通讯作者：
Thomas S. Key
中科院分区：
文献类型：
--
作者：
Shinji Kohara;K. Suzuya;Ken Takeuchi;C. Loong;M. Grimsditch;J. Weber;J. Tangeman;Thomas S. Key
无机玻璃通常表现出一个相互连接的、共价键合的结构元素网络，没有长程有序。在硅酸盐玻璃中，网络形成物是基于通过角落的氧原子相互连接的SiO4四面体。传统观点认为，碱性和碱土正硅酸盐材料不能被玻璃化，因为它们不包含足够的形成网络的二氧化硅来建立所需的互连。研究了无容器熔炼冷却法制备的大块正硅酸镁玻璃。我们发现，网络形体的作用主要是由高度扭曲的离子镁氧物种与氧进行4-，5-和6-配位的角点和边共享承担的。结果表明，在星际空间的无容器环境中也可能发现类似的玻璃相。
Inorganic glasses normally exhibit a network of interconnected, covalent-bonded, structural elements that has no long-range order. In silicate glasses, the network formers are based on SiO4 tetrahedra interconnected through oxygen atoms at the corners. Conventional wisdom implies that alkaline and alkaline-earth orthosilicate materials cannot be vitrified, because they do not contain sufficient network-forming SiO2 to establish the needed interconnectivity. We studied a bulk magnesium orthosilicate glass obtained by containerless melting and cooling. We found that the role of network former was largely taken on by corner and edge sharing of highly distorted, ionic Mg-O species that adopt 4-, 5-, and 6-coordination with oxygen. The results suggest that similar glassy phases may be found in the containerless environment of interstellar space.