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Ab initio simulation of the short‐range order structure of Al ions and substitutional Fe, Cr impurities in S.S. Spinel (MgAl 2 O 4 )
Author(s) -
Votyakov S. L.,
Porotnikov A. V.,
Shchapova Yu. V.,
Yuryeva E. I.,
Ivanovskii A. L.
Publication year - 2004
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.20091
Subject(s) - spinel , octahedron , chemistry , crystallography , cluster (spacecraft) , coordination sphere , ab initio , chromium , ion , impurity , crystal structure , inorganic chemistry , materials science , metallurgy , organic chemistry , computer science , programming language
The structure of the short‐range surrounding of aluminum, ferric iron and chromium octahedrally coordinated cations in s.s. spinel MgAl 2 O 4 :(Fe,Cr) has been established in the framework of the cluster model. The total energy minimum of [ VI Me cent IV Mg 6 VI Al 6 O 38 ] 43‐ clusters (Me cent = Al, Fe, Cr) is realized when oxygens of the first coordination sphere of the central cation VI Me are displaced considerably relative to the initial ideal structure. The displacement depends on the central cation of the cluster. The estimated short‐range order parameters including the oxygen parameter u of the spinel are in satisfactory agreement with experimental data. Comparable analysis of the electronic structure of Al, Fe, Cr cations in octahedral positions of the spinel in ideal and relaxed clusters showed that octahedral distortions should be taken into account when interpreting spectroscopic parameters of the natural spinels and evaluating the charge balance in their structure. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004