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Perovskite (pronunciation: / p ə ˈ r ɒ v s k aɪ t /) is a calcium titanium oxide mineral composed of calcium titanate (chemical formula Ca Ti O 3).Its name is also applied to the class of compounds which have the same type of crystal structure as CaTiO 3, known as the perovskite structure, which has a general chemical formula A 2+ B 4+ (X 2−) 3. [6]
Structure of a perovskite with general chemical formula ABX 3.The red spheres are X atoms (usually oxygens), the blue spheres are B atoms (a smaller metal cation, such as Ti 4+), and the green spheres are the A atoms (a larger metal cation, such as Ca 2+).
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]
Ruddlesden-Popper (RP) phases are a type of perovskite structure that consists of two-dimensional perovskite-like slabs interleaved with cations.The general formula of an RP phase is A n+1 B n X 3n+1, where A and B are cations, X is an anion (e.g., oxygen), and n is the number of octahedral layers in the perovskite-like stack. [1]
In addition to these cations, gold was also shown to be a suitable candidate for cation exchange yielding a mixed-valent, and distorted, perovskite with the composition Cs 2 Au(I)Au(III)Br 6. [102] A-site cation exchange has also been shown to be a viable route for the transformation of CsPbBr 3 to MAPbBr 3 and from CsPbI 3 to FAPbI 3. [82]
The following oxidation–reduction tree for a simple ionic compound, AX, where A is a cation and X is an anion, summarizes the various ways in which intrinsic defects can form. Depending on the cation-to-anion ratio, the species can either be reduced and therefore classified as n-type, or if the converse is true, the ionic species is ...
The typical perovskite structure is represented by the general formula ABX 3, where A and B are cations and X is an anion. When the anion is the ( divalent ) oxide ion, A and B cations can have charges 1 and 5, respectively, 2 and 4, respectively, or 3 and 3, respectively.
The perovskite structure (first identified in the mineral perovskite) occurs in substances with the general formula ABX 3, where A is a metal that forms large cations, typically magnesium, ferrous iron, or calcium. B is another metal that forms smaller cations, typically silicon, although minor amounts of ferric iron and aluminum can occur. X ...