Atomic and Electronic Structure in MgO–SiO 2

Shuseki, Yuta; Kohara, Shinji; Kaneko, Tomoaki; Sodeyama, Keitaro; Onodera, Yohei; Koyama, Chihiro; Masuno, Atsunobu; Sasaki, Shunta; Hatano, Shohei; Shiga, Motoki; Obayashi, Ippei; Hiraoka, Yasuaki; Okada, Junpei T.; Mizuno, Akitoshi; Watanabe, Yuki; Nakata, Yui; Ohara, Koji; Murakami, Motohiko; Tucker, Matthew G.; McDonnell, Marshall T.; Oda, Hirohisa; Ishikawa, Takehiko

doi:10.1021/acs.jpca.3c05561

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Atomic and Electronic Structure in MgO–SiO 2

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Abstract

Understanding disordered structure is difficult due to insufficient information in experimental data. Here, we overcome this issue by using a combination of diffraction and simulation to investigate oxygen packing and network topology in glassy (g-) and liquid (l-) MgO–SiO 2 based on a comparison with the crystalline topology. We find that packing of oxygen atoms in Mg 2 SiO 4 is larger than that in MgSiO 3 , and that of the glasses is larger than that of the liquids. Moreover, topological analysis suggests that topological similarity between crystalline (c)- and g-(l-) Mg 2 SiO 4 is the signature of low glass-forming ability (GFA), and high GFA g-(l-) MgSiO 3 shows a unique glass topology, which is different from c-MgSiO 3 . We also find that the lowest unoccupied molecular orbital (LUMO) is a free electron-like state at a void site of magnesium atom arising from decreased oxygen coordination, which is far away from crystalline oxides in which LUMO is occupied by oxygen’s 3s orbital state in g- and l-MgO–SiO 2 , suggesting that electronic structure does not play an important role to determine GFA. We finally concluded the GFA of MgO–SiO 2 binary is dominated by the atomic structure in terms of network topology.

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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY amorphous materials chemical structure liquids oxygen x-rays

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Shuseki, Yuta, Kohara, Shinji, Kaneko, Tomoaki, Sodeyama, Keitaro, Onodera, Yohei, Koyama, Chihiro, Masuno, Atsunobu, Sasaki, Shunta, Hatano, Shohei, Shiga, Motoki, Obayashi, Ippei, Hiraoka, Yasuaki, Okada, Junpei T., Mizuno, Akitoshi, Watanabe, Yuki, Nakata, Yui, Ohara, Koji, Murakami, Motohiko, Tucker, Matthew G., McDonnell, Marshall T., Oda, Hirohisa, Ishikawa, Takehiko. 2024-01-18. Atomic and Electronic Structure in MgO–SiO 2. https://doi.org/10.1021/acs.jpca.3c05561

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