These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: High-pressure preparation, crystal structure, and properties of alpha-(RE)2B4O9 (RE=Eu, Gd, Tb, Dy): oxoborates displaying a new type of structure with edge-sharing BO4 tetrahedra.
    Author: Emme H, Huppertz H.
    Journal: Chemistry; 2003 Aug 04; 9(15):3623-33. PubMed ID: 12898690.
    Abstract:
    High-pressure/high-temperature conditions of 10 GPa and 1150 degrees C were used to synthesize the new rare-earth oxoborates alpha-(RE)(2)B(4)O(9) (RE=Eu, Gd, Tb, Dy) in a Walker-type multianvil apparatus. Single-crystal X-ray structure determination of alpha-(RE)(2)B(4)O(9) (RE=Eu, Gd, Tb) revealed: C2/c, Z=20, alpha-Eu(2)B(4)O(9): a=2547.9(5), b=444.3(1), c=2493.8(5) pm, beta=99.82(3) degrees, R1=0.0277, wR2=0.0693 (all data); alpha-Gd(2)B(4)O(9): a=2539.0(1), b=443.3(1), c=2490.8(1) pm, beta=99.88(1) degrees, R1=0.0457, wR2=0.0643 (all data); alpha-Tb(2)B(4)O(9): a=2529.4(1), b=441.6(1), c=2484.3(1) pm, beta=99.88(1) degrees, R1=0.0474, wR2=0.0543 (all data). The isotypic compounds exhibit a new type of structure that is built up of BO(4) tetrahedra to form a network that incorporates the rare-earth cations. The most important feature is the existence of the new structural motif of edge-sharing BO(4) tetrahedra next to the known motif of corner-sharing BO(4) tetrahedra, which is realized in the presented compounds alpha-(RE)(2)B(4)O(9) (RE=Eu, Gd, Tb, Dy) for the second time. Furthermore, we report the temperature-resolved in-situ powder-diffraction measurements, DTA, IR/Raman spectroscopic investigations, and magnetic properties of the new compounds.
    [Abstract] [Full Text] [Related] [New Search]