ChemInform Abstract: Cr3Si2O7×1/4MX (MX: NaCl, NaBr, KCl, KBr): A Cage Structure Built from (CrIIO4) and (Si2O7) Units.

✍ Scribed by A. SCHMIDT; R. GLAUM

• Book ID: 101853225
• Publisher: John Wiley and Sons
• Year: 2010
• Weight: 31 KB
• Volume: 28
• Category: Article
• ISSN: 0931-7597
• DOI: 10.1002/chin.199751034

✦ Synopsis

Built from (CrIIO4) and (Si2O7) Units. -Purple crystals of the new title compounds are prepared by reaction of Cr2O3, Cr, SiO2, and MX for 2 d at 1620 K and characterized by single-crystal XRD and magnetic measurements. The structure of the isotypic compounds (tetragonal, I4/mmm, Z = 8), which can be described as an expanded NaCl type, consists of two crystallographically different Cr( II) atoms in square planar oxygen coordination which form bent trimers (Cr3O4O4/2). Connection of four trimers by edge-sharing results in a ( Cr12O24) cage in which the halide ion is located. Na+ and K+ reside in a second type of cages formed by linking (Cr12O24) units by disilicate groups. The compounds exhibit strong low-dimensional antiferromagnetic coupling of Cr(II) ions. -(SCHMIDT, A.