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| Untersuchte Arbeit: Seite: 33, Zeilen: 9-18 |
Quelle: Wikipedia Silicon dioxide 2011 Seite(n): online, Zeilen: - |
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| In the vast majority of silicates, the Si atom shows tetrahedral coordination, with 4 oxygen atoms surrounding a central Si atom. The most common example is seen in the quartz crystalline form of silica SiO2. In each of the thermodynamically most stable crystalline forms of silica, on average, all 4 of the vertices (or oxygen atoms) of the SiO4 tetrahedron are shared with others, yielding the net chemical formula: SiO2
Figure 3.2 Tetrahedral structural unit of silica (SiO4), the basic building block of the most ideal glass former The amorphous structure of glassy silica (SiO2) is in two-dimensions. No long-range order is present; however there is local ordering with respect to tetrahedral arrangement of oxygen (O) atoms around the silicon (Si) atoms. Note that a fourth oxygen atom is bonded to each silicon atom, either behind the plane of the screen or in front of it; these atoms are omitted for clarity. |
Tetrahedral structural unit of silica (SiO4), the basic building block of the most ideal glass former. In the vast majority of silicates, the Si atom shows tetrahedral coordination, with 4 oxygen atoms surrounding a central Si atom. The most common example is seen in the quartz crystalline form of silica SiO2. In each of the most thermodynamically stable crystalline forms of silica, on average, all 4 of the vertices (or oxygen atoms) of the SiO4 tetrahedra are shared with others, yielding the net chemical formula: SiO2. [...] The amorphous structure of glassy silica (SiO2) in two-dimensions. No long-range order is present; however there is local ordering with respect to the tetrahedral arrangement of oxygen (O) atoms around the silicon (Si) atoms. Note that a fourth oxygen atom is bonded to each silicon atom, either behind the plane of the screen or in front of it; these atoms are omitted for clarity. |
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