“…[5][6][7][8][9] Meanwhile, theoretical investigations based on ab initio molecular dynamics ͑MD͒, tight-binding MD, and classical MD study or Monte Carlo simulations using various empirical potentials have also been carried out. 4,[10][11][12][13][14][15][16][17][18][19][20][21][22] Compared with the intensive reports about chemical or-der, the knowledge of topological SRO and MRO is limited. 4,[11][12][13]15,17,20 Although the tetrahedral unit is generally taken into account for a measure of SRO, the mediumrange picture, involving how these units are connected, is not yet clear, with a specific definition of MRO still wanted.…”