Electron Density Study of Garnets: Y3X2Al3O12;X=Al andX=(Al, Cr)

✍ Scribed by Haruo Sawada

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 380 KB
• Volume: 134
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1997.7573

✦ Synopsis

The electron density distribution in two garnets Y 3 Al 2 Al 3 O 12 [YAG] and Y 3 X 2 Al 3 O 12 : X ‫؍‬ (Al 0.71 Cr 0.29 ) [YCG] have been studied with single-crystal X-ray diffraction methods through scattering factor refinement procedures. YAG has broad electron density residuals of 0.3 e/A s 3 height extending between the octahedral Al site and the coordinated oxygen atoms. YCG shows residuals around the Y and oxygen sites indicating significant anharmonicity, along with electron density deformation of the X-site characteristic of octahedral Cr 3؉ sites. Partial substitution of Al by Cr in the X site does not increase the unshared O-O distance or the far Y-O distance in the adjacent Y site. [Cubic Ia3 d, Z ‫؍‬ 8. For YAG, a ‫؍‬ 12.0095(4) A s ; D x ‫؍‬ 4.553 g/cm 3 ;