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Investigation of chemical bond characteristics, thermal expansion coefficients and bulk moduli of α‐R 2 MoO 6 and R 2 Mo 2 O 7 (R = rare earths) by using a dielectric chemical bond method
Author(s) -
Li Huaiyong,
Zhang Siyuan,
Zhou Shihong,
Cao Xueqiang
Publication year - 2009
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.21193
Subject(s) - thermal expansion , bulk modulus , ionic radius , materials science , pyrochlore , chemical bond , thermodynamics , lanthanide , bond length , ionic bonding , compressibility , crystallography , analytical chemistry (journal) , ion , chemistry , crystal structure , metallurgy , physics , composite material , organic chemistry , chromatography , phase (matter)
Theoretical researches are performed on the α‐R 2 MoO 6 (R = Y, Gd, Tb Dy, Ho, Er, Tm and Yb) and pyrochlore‐type R 2 Mo 2 O 7 (R = Y, Nd, Sm, Gd, Tb and Dy) rare earth molybdates by using chemical bond theory of dielectric description. The chemical bonding characteristics and their relationship with thermal expansion property and compressibility are explored. The calculated values of linear thermal expansion coefficient (LTEC) and bulk modulus agree well with the available experimental values. The calculations reveal that the LTECs and the bulk moduli do have linear relationship with the ionic radii of the lanthanides: the LTEC decreases from 6.80 to 6.62 10 −6 /K and the bulk modulus increases from 141 to 154 GPa when R goes in the order Gd, Tb Dy, Ho, Er, Tm, and Yb in the α‐R 2 MoO 6 series; while in the R 2 Mo 2 O 7 series, the LTEC ranges from 6.80 to 6.61 10 −6 /K and the bulk modulus ranges from 147 to 163 GPa when R varies in the order Nd, Sm, Gd, Tb and Dy. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2009