amorphous

Amorphous solids in a non-crystalline state are thermodynamically non-equilibrium phases formed when supercooled liquids freeze. Since there is no long-range order seen in crystals, a slow peak called a halo is observed in X-ray diffraction. There is short-range order between adjacent atoms, which is characterized by the coordination number, bond distance, and angle of the adjacent atoms. The short-range structure of quartz glass, a typical oxide glass, is _SiO4 tetrahedrons, and the compound rings connecting these tetrahedrons form a long-range irregular network structure. The short-range structure of amorphous metals is a close-packed disordered packing of hard spheres packed together in a disordered manner, and the polyhedra connecting the vertices of these hard spheres are connected three-dimensionally.

Source: Morikita Publishing "Chemical Dictionary (2nd Edition)" Information about the Chemical Dictionary 2nd Edition

非晶質状態のアモルファス固体は，過冷却液体が凍結した熱力学的非平衡相である．結晶にみられる長距離秩序がないことから，X線回折ではハローとよばれる緩慢なピークが観測される．近接する原子間では短距離秩序をもち，隣接原子の配位数，結合距離，角度で特徴づけられる．代表的な酸化物ガラスである石英ガラスの短範囲構造はSiO₄四面体であり，これら四面体を連結する複員環が長範囲の不規則網目構造を形成する．アモルファス金属の短範囲構造は，剛体球を無秩序に詰め込んだ最密無秩序充填であり，これら剛体球の頂点を結ぶ多面体が三次元的に連結する．

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