Synthesis and crystal structure of new layered BaNaSc(BO 3) 2 and BaNaY(BO 3) 2 orthoborates

• Published in: Journal of solid state chemistry 2010-05, Vol.183 (5), p.1200-1204
• Main Authors: Seryotkin, Yurii V., Bakakin, Vladimir V., Kokh, Aleksandr E., Kononova, Nadezhda G., Svetlyakova, Tatyana N., Kokh, Konstantin A., Drebushchak, Tatyana N.
• Format: Article
• Language: English
• Subjects: Layered orthoborates; Melt–solution crystallization; Single crystal X-ray analysis; Unilateral coordination of Na
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/j.jssc.2010.03.005

Crystals of two new layered BaNaSc(BO 3) 2 ( I) and BaNaY(BO 3) 2 ( II) orthoborates are grown from the melt-solution by the spontaneous crystallization onto the platinum loop. Single crystal X-ray analysis showed that the compounds are isostructural with the space group R3¯, a=5.23944(12) and 5.3338(2) Å, and c=34.5919(11) and 35.8303(19) Å for I and II, respectively, Z=6. The distinctive feature of the structure is the close-packed composite anion–cation (Ba,Na)(BO 3) layers. The layers are combined into the base building packages of two types: { M 3+[Ba 2+(BO 3) 3−] 2} + and { M 3+[Na +(BO 3) 3−] 2} −, where M is Sc or Y. Neutral-charge two-package (four-layer) blocks are stacked by the rhombohedral principle into twelve layers of the cubic packing. The distinctive feature of new orthoborate crystals BaNaSc(BO 3) 2 and BaNaY(BO 3) 2 is the combination of base building packages of two types: { M 3+[Ba 2+(BO 3) 3–] 2} + and { M 3+[Na +(BO 3) 3–] 2} –, where M is Sc or Y.