Synthesis, Crystal Structures, and Properties of Edge-Sharing Tetrahedra Centered with Silicon and Cobalt: Cs2CoSiO4 and Cs5CoSiO6

✍ Scribed by Jens Hansing; Angela Möller

• Book ID: 102975091
• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 566 KB
• Volume: 162
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.2001.9248

✦ Synopsis

IN HONOR OF PROFESSOR PAUL HAGENMULLER ON THE OCCASION OF HIS 80TH BIRTHDAY Cs 2 CoSiO 4 and Cs 5 CoSiO 6 were obtained from reactions of Cs 2 O, CdO, and SiO 2 with cobalt plates in Ag containers which were encapsulated in glass ampoules under an Ar atmosphere. Cs 5 CoSiO 6 is formed at 3503C (40 d) and Cs 2 CoSiO 4 at 4503C (30 d) in an oxidation process under reduction of Cd 2 ؉ to the metal. Cs 2 CoSiO 4 crystallizes in the space group Cmc2 1 (a ‫؍‬ 582.5(1) pm, b ‫؍‬ 1243.3(3) pm, c ‫؍‬ 815.7(1) pm, R all ‫؍‬ 0.066) and Cs 5 CoSiO 6 in P2 1 /n (a ‫؍‬ 670.57(7) pm, b ‫؍‬ 1080.8(2) pm, c ‫؍‬ 1646.1( 2) pm, ‫؍‬ 94.89(1)3, R all ‫؍‬ 0.052). Both compounds have the characteristic feature of edge-sharing tetrahedra centered with cobalt and silicon, forming dimers in common. Magnetic and luminescence measurements were carried out for Cs 2 CoSiO 4 , and UV+VIS+NIR+MIR+FIR spectra were recorded for both compounds. The electronic structures are described in terms of the angular overlap model.