Synthesis and crystal structure of new layered BaNaSc(BO3)2 and BaNaY(BO3)2 orthoborates

Crystals of two new layered BaNaSc(BO3)2 (I) and BaNaY(BO3)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)(BO3) layers. The layers are combined into the base building packages of two types: {M3+[Ba2+(BO3)3−]2}+ and {M3+[Na+(BO3)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.

Graphical abstractThe distinctive feature of new orthoborate crystals BaNaSc(BO3)2 and BaNaY(BO3)2 is the combination of base building packages of two types: {M3+[Ba2+(BO3)3–]2}+ and {M3+[Na+(BO3)3–]2}–, where M is Sc or Y.Figure optionsDownload full-size imageDownload as PowerPoint slide