X-RAY-POWDER DIFFRACTION AS A TOOL FOR FACING TWINS - THE CASE OF THE MONOCLINIC NBCOTE2 AND TACOTE2 PHASES
Articolo
Data di Pubblicazione:
1993
Citazione:
X-RAY-POWDER DIFFRACTION AS A TOOL FOR FACING TWINS - THE CASE OF THE MONOCLINIC NBCOTE2 AND TACOTE2 PHASES / J. LI, F. MCCULLEY, S. MCDONNELL, N. MASCIOCCHI, D.M. PROSERPIO, A. SIRONI. - In: INORGANIC CHEMISTRY. - ISSN 0020-1669. - 32:22(1993), pp. 4829-4833.
Abstract:
TaCoTe2 has been synthesized from the elements at 900-degrees-C in evacuated silica tubes; the crystals of TaCoTe2 are monoclinic, space group P2(1)/c (No. 14), with a = 8.1524(6) angstrom, b = 6.2649(4) angstrom, c = 7.7945(5) angstrom, beta = 116.789(4)-degrees, and Z=4, and appear to be heavily twinned about the (100) plane. Therefore, powder diffraction data and Rietveld refinement were used to assess the correct stereochemistry of the atoms of this new compound. In addition, the already reported NbCoTe2 compound has been found to be, in the bulk, monoclinic [a = 8.1612(4) angstrom, b = 6.2976(3) angstrom, c = 7.8518(4) angstrom, beta = 117.487(3)-degrees], rather than orthorhombic, and isostructural to TaCoTe2. The stereochemical interpretation of this change of crystal symmetry is given in terms of a significant asymmetrical bending of one tellurium atom toward one Nb (or Ta) atom, making these metals five-, rather than six-, coordinated.
Tipologia IRIS:
01 - Articolo su periodico
Elenco autori:
J. LI, F. MCCULLEY, S. MCDONNELL, N. MASCIOCCHI, D.M. PROSERPIO, A. SIRONI
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