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Perovskite Compounds (perovskite + compound)
Selected AbstractsStructural Change in a Series of Protonated Layered Perovskite Compounds, HLnTiO4 (Ln: La, Nd and Y).CHEMINFORM, Issue 39 2006Shunsuke Nishimoto Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Microstructure Characterizations in Calcium Magnesium NiobateJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 7 2001Hwack Joo Lee Microstructural studies on the domain boundaries in Ca(Mg1/3CNb2/3)O3 (CMN) complex perovskite compound were conducted using X-ray diffractometry and transmission electron microscopy. The 1:2 chemical ordering of B-site cations and the tilting of oxygen octahedra were involved in the CMN microstructure, as inferred from the presence of two types of domain boundaries. One type was the antiphase boundaries (APBs), which did not lie on a specific set of crystallographic planes. These boundaries were caused by the chemical 1:2 ordering of B-site cations, magnesium and niobium. The other type was the ferroelastic domain boundaries, which were parallel to a certain crystallographic plane. Therefore, CMN had the 1:2 ordered monoclinic unit cell distorted by the antiphase or in-phase tilting of oxygen octahedra. CMN had the mixed phases rather than the homogeneous phase. [source] Relationship between the Bond Valence and the Temperature Coefficient of the Resonant Frequency in the Complex Perovskite (Pb1,xCax)[Fe0.5(Nb1,yTay)0.5]O3JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 1 2001Heung Soo Park The temperature coefficient of the resonant frequency (TCF) of complex perovskite (Pb1,xCax)[Fe0.5(Nb1,yTay)0.5]O3 ceramics (x= 0.5, 0.55; 0.0 ,y, 1.0) was investigated, relative to the bond valence of the A- and B-site ions in the ABO3 perovskite structure (such as the barium-, strontium-, and calcium-based complex perovskites). The TCF of these complex perovskite compounds varied with the bond valence of the A- and B-sites and the tolerance factor (t) in the perovskite structure. In the tilted region (t < 1.0), the tilting of the oxygen octahedra increased and the TCF decreased, because of the increased bond valence of the B-site. Also, the dependence of TCF on the bond valence of the A-site was similar to its dependence on t. [source] Structural stability and formability of ABO3 -type perovskite compoundsACTA CRYSTALLOGRAPHICA SECTION B, Issue 6 2007Huan Zhang On the basis of the bond-valence model (BVM) and structure-map technology, the structural stability and formability of ABO3 -type perovskite compounds were investigated in 376 ABO3 -type compounds. A new criterion of structural stability for ABO3 -type perovskite compounds has been established by the bond-valence calculated tolerance factors, which are in the range 0.822,1.139. All global instability indices for ABO3 -type perovskite compounds are found to be less than 1.2,v.u. (valence units) and increase with a decrease in oxidation state of the B cations (i.e. structural stability in the formation of an ideal cubic perovskite follows the order A+B5+O3 -type > A2+B4+O3 -type > A3+B3+O3 -type). Three new two-dimensional structure maps were constructed based on the ideal A,O and B,O bond distances derived from the BVM. These maps indicate the likelihood of particular perovskite compounds being formed. The present work enables novel perovskite and perovskite-related compounds to be explored by screening all the possible elemental combinations in future crystal engineering. [source] | ||||||||||