کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1331448 | 979005 | 2007 | 12 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Phase stabilities of monoclinic oxoborates LaB3O6 and GdB3O6 in C121 and I12/a1 phase—Energetics and chemical bonds derived from first-principles calculations Phase stabilities of monoclinic oxoborates LaB3O6 and GdB3O6 in C121 and I12/a1 phase—Energetics and chemical bonds derived from first-principles calculations](/preview/png/1331448.png)
The computational study on the relative phase stabilities between two monoclinic polymorphs of the lanthanide-containing oxoborates LaB3O6 and GdB3O6 is presented at the first-principles density functional theory gradient-corrected B3PW level. The hypothetical monoclinic α-BiB3O6-like C121 non-centrosymmetric crystal structures were assumed for LaB3O6 and GdB3O6 and the corresponding geometries were calculated and compared with their monoclinic I12/a1 centrosymmetric structures. The enthalpy–pressure correlations were calculated and the first-principles chemical bonds based on the crystal orbital overlapping population were quantitatively analyzed for LaB3O6 and GdB3O6. The chemical bonds between the central cation (La (III)/Gd (III)) and coordinated oxygen atoms rather than the B–O bonds in the borate units are found to stabilize the I12/a1 centrosymmetric LaB3O6 and GdB3O6 structures with respect to the C121 non-centrosymmetric counterparts.
The electronic structures, energetics and metal–oxygen chemical bonds have been calculated for both monoclinic phases in the space groups of centrosymmetric I2/a (left) and noncentrosymmetric C2 (right) for LaB3O6 and GdB3O6, respectively, by the gradient corrected hybrid density functional theory.Figure optionsDownload as PowerPoint slide
Journal: Journal of Solid State Chemistry - Volume 180, Issue 10, October 2007, Pages 2763–2774