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The same structure occurs in so-called meta-vanadates, such as ammonium metavanadate, NH 4 VO 3. The formula of the oxyanion SiO 2− 3 is obtained as follows: each nominal silicon ion (Si 4+) is attached to two nominal oxide ions (O 2−) and has a half share in two others. Thus the stoichiometry and charge are given by:
An oxide (/ ˈ ɒ k s aɪ d /) is a chemical compound containing at least one oxygen atom and one other element [1] in its chemical formula. "Oxide" itself is the dianion (anion bearing a net charge of –2) of oxygen, an O 2– ion with oxygen in the oxidation state of −2. Most of the Earth's crust consists of oxides. Even materials ...
Cations and anions are also typically discrete and can be depicted unambiguously. For simple structures, say <10 atoms, it is helpful to depict all atoms explicitly. For more complex molecules, most hydrogen atoms attached to carbon are omitted, and carbon atoms are represented by vertices.
The perovskite structure is frequently found for ternary oxides formed with one large (A) and one small cation (B). In this structure, there is a simple cubic array of B cations, with the A cations occupying the center of the cube, and the oxide atoms are sited at the center of the 12 edges of the simple cube. [8] [5] [6] [7]
The structure of sodium oxide has been determined by X-ray crystallography.Most alkali metal oxides M 2 O (M = Li, Na, K, Rb) crystallise in the antifluorite structure.In this motif the positions of the anions and cations are reversed relative to their positions in CaF 2, with sodium ions tetrahedrally coordinated to 4 oxide ions and oxide cubically coordinated to 8 sodium ions.
Inverse spinel structures have a different cation distribution in that all of the A cations and half of the B cations occupy octahedral sites, while the other half of the B cations occupy tetrahedral sites. An example of an inverse spinel is Fe 3 O 4, if the Fe 2+ (A 2+) ions are d 6 high-spin and the Fe 3+ (B 3+) ions are d 5 high-spin.
Ionic compounds containing hydrogen ions (H +) are classified as acids, and those containing electropositive cations [57] and basic anions ions hydroxide (OH −) or oxide (O 2−) are classified as bases. Other ionic compounds are known as salts and can be formed by acid–base reactions. [58]
2D diagram of mellitate C 12 O 6− 12, one of the oxocarbon anions. Black circles are carbon atoms, red circles are oxygen atoms. Each blue halo represents one half of a negative charge. In chemistry, an oxocarbon anion is a negative ion consisting solely of carbon and oxygen atoms, and therefore having the general formula C x O n−