Perovskite general chemical formula

The typical chemical formula of the perovskite structure is ABO3, where A and B denote two different cations. The ilmenite structure has the same composition as the perovskite one, i.e., ABO3 however, A and B in this structure are cations of approximately the same size that occupy an octahedral site. Therefore, in spite of the fact that they share the same general chemical formula, structures classified as ilumenite or ilmenite-related structure (e.g., LiSb03) are different from perovskite. 

AxByOz Compounds (Bmnzes). The bronzes are channel stmctures with an openness that allows for the transport of atoms or ions into the crystal. Bronzes have the general formula AJiyO, in which A is an alkali-, alkaline-earth, or rare-earth metal and B can be Ti, V, Mn, Nb, Mo, Ta, W, or Re. The German chemist Friedrich Wohler (1800-1882), who discovered Na jWOs in 1824, called these materials bronzes owing to their intense color and metalhc luster. The introduction of sodium into the WO3 perovskite stmcture chemically reduces a portion of the W ions to When... 

The acceptor-doped perovskites (general formula of ABOs-a) have shown much promise as MIECs. Much attention has been focused on these versatile metal oxides as they exhibit catalytic activity [24] and therefore their use in some applications can avoid the need for catalytic modification of the membrane surface. This activity has meant that MIECs can be used as electrode materials in solid-oxide fuel cell systems for the reduction of oxygen simultaneously, this inherent catalytic activity means that problems with chemical stability can arise. 

Multiferroic materials with double-perovskite structure aA BB O ) are solid solutions of two perovskites ABO and [a B O3). In [aa BB oj, A and A represent alkaline rare earth cations (La, Y, and Ce), while B and B are transition metal cations (Ni and Co). If A and A represent the same chemical element, the double perovskite has the general formula (AjBB O ) and the crystal structure of A B B Og -type perovskite, as shown in Figure 2. Alkali-earth and lanthanide (smaller ion) ions are alone usually occupied in the A site [27,28]. If the A ion is too small, the common expected distortions are cation displacement with BOg and octahedral ones [29]. 

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