Search results
Results from the WOW.Com Content Network
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 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]
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.
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 ...
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.
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.
In condensed matter physics and inorganic chemistry, the cation-anion radius ratio can be used to predict the crystal structure of an ionic compound based on the relative size of its atoms. It is defined as the ratio of the ionic radius of the positively charged cation to the ionic radius of the negatively charged anion in a cation-anion ...
The oxide ion has an ionic radius of 1.40 Å, molybdenum(VI) is much smaller, 0.59 Å. [1] There are strong similarities between the structures of the molybdates and the molybdenum oxides, ( MoO 3 , MoO 2 and the " crystallographic shear " oxides, Mo 9 O 26 and Mo 10 O 29 ) whose structures all contain close packed oxide ions.