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Structure and Properties of γ‐Brass‐Type Pt 2 Zn 11—δ (0.2 < δ < 0.3)
Author(s) -
Harbrecht B.,
Thimmaiah S.,
Armbrüster M.,
Pietzonka C.,
Lee S.
Publication year - 2002
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/1521-3749(200212)628:12<2744::aid-zaac2744>3.0.co;2-a
Subject(s) - crystallography , crystal structure , octahedron , chemistry , zinc , rietveld refinement , diamagnetism , atom (system on chip) , metal , physics , organic chemistry , computer science , embedded system , quantum mechanics , magnetic field
The γ‐brass type phase Pt 2 Zn 11—δ (0.2 < δ < 0.3) was prepared by reaction of the elements in evacuated silica ampoules. The structures of crystals grown in the presence of excess zinc or alternatively excess platinum were determined from single crystal X‐ray diffraction intensities and confirmed by Rietveld profile fits. Pt 2 Zn 10.72(1) crystallizes in the space group I4¯3m, a = 908.55(4) pm, Z = 4. The structure refinement converged at R F = 0.0302 for I o > 2σ (I o ) for 293 symmetrically independent intensi ties and 19 variables. The structure consists of a 26 atom cluster which is comprised of four crystallographically distinct atoms. The atoms Zn(1), Pt(1), Zn(2) and Zn(3) form an inner tetrahedron IT, an outer tetrahedron OT, an octahedron OH, and a distorted cuboctahedron CO respectively. About 14 % of the Zn(1) sites are unoccupied. Pt 2 Zn 10.73 melts at 1136(2) K. It is a moderate metallic conductor (ρ 298 = 0.2—0.9 mΩ cm) whose magnetic properties (χ mol = —4.6 10 —10 to —5.4 10 —10 m 3 mol —1 ) are dominated by the core diamagnetism of its components.