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High‐Pressure Synthesis and Characterization of New Actinide Borates, An B 4 O 8 ( An =Th, U)
Author(s) -
Hinteregger Ernst,
Hofer Thomas S.,
Heymann Gunter,
Perfler Lukas,
Kraus Florian,
Huppertz Hubert
Publication year - 2013
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201302378
Subject(s) - actinide , boron , monoclinic crystal system , crystallography , thorium , crystal structure , raman spectroscopy , chemistry , oxide , lattice (music) , uranium , materials science , inorganic chemistry , physics , metallurgy , organic chemistry , acoustics , optics
New actinide borates ThB 4 O 8 and UB 4 O 8 were synthesized under high‐pressure, high‐temperature conditions (5.5 GPa/1100 °C for thorium borate, 10.5 GPa/1100 °C for the isotypic uranium borate) in a Walker‐type multianvil apparatus from their corresponding actinide oxide and boron oxide. The crystal structure was determined on basis of single‐crystal X‐ray diffraction data that were collected at room temperature. Both compounds crystallized in the monoclinic space group C 2/ c ( Z =4). Lattice parameters for ThB 4 O 8 : a =1611.3(3), b =419.86(8), c =730.6(2) pm; β =114.70(3)°; V =449.0(2) Å 3 ; R 1 =0.0255, wR 2 =0.0653 (all data). Lattice parameters for UB 4 O 8 : a =1589.7(3), b =422.14(8), c =723.4(2) pm; β =114.13(3)°; V =443.1(2) Å 3 ; R 1 =0.0227, wR 2 =0.0372 (all data). The new An B 4 O 8 (An= Th, U) structure type is constructed from corner‐sharing BO 4 tetrahedra, which form layers in the bc plane. One of the four independent oxygen atoms is threefold‐coordinated. The actinide cations are located between the boron–oxygen layers. In addition to Raman spectroscopic investigations, DFT calculations were performed to support the assignment of the vibrational bands.