The Crystal Structures of the Strontium Gallates Sr10Ga6O19 and Sr3Ga2O6

✍ Scribed by V. Kahlenberg

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 613 KB
• Volume: 160
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.2001.9259

✦ Synopsis

The crystal structures of Sr 10 Ga 6 O 19 and Sr 3 Ga 2 O 6 have been characterized using X-ray di4raction techniques. In the case of Sr 10 Ga 6 O 19 , the structure was determined from a single crystal di4raction data set collected at room conditions and re5ned to a 5nal R index of 0.061 for 3471 observed re6ections (I'2 (I)). The compound is monoclinic with space group C12/c1 (a ‫؍‬ 34.973(4) A s , b ‫؍‬ 7.934(1) A s , c ‫؍‬ 15.943(2) A s , ‫؍‬ 103.55(1)3, V ‫؍‬ 4300.7(6) A s 3 , Z ‫؍‬ 8, D calc ‫؍‬ 4.94 g/cm 3 , (MoK ) ‫؍‬ 32.04 mm ؊ 1 ) and can be classi5ed as an oligogallate. It is the 5rst example of an inorganic compound where six [TO 4 ]tetrahedra of only one chemical species occupying the tetrahedral centres are linked via bridging oxygen atoms to form [T 6 O 19 ] groups. The hexamers are not linear, but highly puckered. Eleven symmetrically di4erent Sr cations located in planes parallel (100) crosslink between the oligo-groups. They are coordinated by six to eight oxygen ligands. The structure of Sr 3 Ga 2 O 6 has been re5ned from powder di4raction data using the Rietveld method (space group Pa3 , a ‫؍‬ 16.1049(1), V ‫؍‬ 4177.1(1) A s 3 , Z ‫؍‬ 24, D calc ‫؍‬ 4.75 g/cm 3 ). The compound is isostructural with tricalcium aluminate and contains highly puckered, six-membered [Ga 6 O 18 ] 18 ؊ rings. The rings are linked by strontium cations having six to nine nearest oxygen neighbors.