Acta Phys. -Chim. Sin. ›› 2005, Vol. 21 ›› Issue (07): 769-773.doi: 10.3866/PKU.WHXB20050714

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Synthesis and Structure of La[B5O8(OH)(H2O)]NO3•2H2O

LI Lin-yan; LI Guo-bao; LIAO Fu-hui; LIN Jian-hua   

  1. State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871
  • Received:2004-12-23 Revised:2005-02-22 Published:2005-07-15
  • Contact: LIN Jian-hua E-mail:jhlin@pku.edu.cn

Abstract: Boric acid is used as a flux and reactant to synthesize a novel hydrated rare earth polyborate, La[B5O8(OH)(H2O)]NO3•2H2O. The structure of the title compound is established by single X-ray diffraction data. It crystallizes in monoclinic structures (P21/n) and consists of a double three-membered ring composed of three BO4 and two BO3 groups as the fundamental building block (FBB). The FBB shares four common oxygen atoms with thethe adjacent FBBs producing a borate layer containing nine-membered borate ring window. Lanthanum cations are located around the center of the nine-membered ring. The borate layers are stacked along the b axis and are interlinked by the La-O bond. Nitrate ions and some water molecules are sandwiched between the borate layers. This study further demonstrates that the low temperature synthesis approach by using molten boric acid as a flux is effective for the syntheses of hydrated rare earth polyborates.

Key words: Rare earth borate, Synthesis, Crystal structure