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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 ...
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:
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.
The oxide crystal structure is based on a close-pack array of oxygen anions, with metal cations occupying interstitial sites. [1] The close-packed arrays, such as face-centered-cubic (fcc) and hexagonal-close packed (hcp), have both octahedral and tetrahedral interstices. [3]
K 2 O crystallises in the antifluorite structure. In this motif the positions of the anions and cations are reversed relative to their positions in CaF 2, with potassium ions coordinated to 4 oxide ions and oxide ions coordinated to 8 potassium. [6] [7] K 2 O is a basic oxide and reacts with water violently to produce the caustic potassium ...
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]
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.
Like many monoxides, MnO adopts the rock salt structure, where cations and anions are both octahedrally coordinated.Also like many oxides, manganese(II) oxide is often nonstoichiometric: its composition can vary from MnO to MnO 1.045.