Syntheses, thermal stability, and structure determination of the novel isostructural RBa3B9O18 (R = Y, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb)

X Z Li; C Wang; X L Chen; H Li; L S Jia; L Wu; Y X Du; Y P Xu

doi:10.1021/ic049710m

Syntheses, thermal stability, and structure determination of the novel isostructural RBa3B9O18 (R = Y, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb)

Inorg Chem. 2004 Dec 27;43(26):8555-60. doi: 10.1021/ic049710m.

Authors

X Z Li¹, C Wang, X L Chen, H Li, L S Jia, L Wu, Y X Du, Y P Xu

Affiliation

¹ Nanoscale Physics and Device Lab, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100080, People's Republic of China.

PMID: 15606206
DOI: 10.1021/ic049710m

Abstract

A novel borate compound YBa(3)B(9)O(18) has crystallized in a melt of BaYB(9)O(16). Single-crystal X-ray diffraction measurements reveal that YBa(3)B(9)O(18) adopts a hexagonal space group P6(3)/m with cell parameters of a = 7.1761(6) A and c = 16.9657(6) A. The structure is made up of the planar B(3)O(6) groups parallel to each other along the (001) direction, regular YO(6) octahedra, and irregular BaO(6) and BaO(9) polyhedra to form an analogue structure of beta-BaB(2)O(4). A series of isostructural borate compounds RBa(3)B(9)O(18) (R = Y, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb) were prepared by powder solid-state reactions. The DTA and TGA curves of YBaB(9)O(16) show an obvious weight loss at about 955 degrees C associated with a decomposition into YBO(3), B(2)O(3), and YBa(3)B(9)O(18) due to its incongruent melting behavior. The DTA and TGA curves of YBa(3)B(9)O(18) show that it is chemically stable and a congruent melting compound. A comparison of the structures of YBa(3)B(9)O(18) and beta-BaB(2)O(4) is presented.