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Infinite Linear Zinc Chains in A Au 4 Zn 2 ( A = Ca, Ce, Pr, Nd) with YbAl 4 Mo 2 Type Structure
Author(s) -
Gerke Birgit,
Niehaus Oliver,
Hoffmann RolfDieter,
Pöttgen Rainer
Publication year - 2013
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/zaac.201300260
Subject(s) - paramagnetism , praseodymium , zinc , crystallography , cerium , magnetic susceptibility , intermetallic , lanthanide , tantalum , chemistry , superstructure , crystal structure , materials science , analytical chemistry (journal) , inorganic chemistry , metallurgy , condensed matter physics , ion , physics , oceanography , organic chemistry , alloy , chromatography , geology
The intermetallic zinc compounds A Au 4 Zn 2 ( A = Ca, Ce, Pr, Nd) were obtained by induction melting of the elements in sealed tantalum tubes. The samples were studied by X‐ray diffraction on powders. The structures of the calcium and the cerium compound were refined from single crystal diffraction data: YbAl 4 Mo 2 type, I 4/ mmm , a = 692.8(1), c = 527.6(1) pm, wR 2 = 0.0304, 244 F 2 values and 11 variables for CaAu 4.08 Zn 1.92 and a = 699.6(1), c = 531.2(1) pm, wR 2 = 0.1152, 186 F 2 values and 10 variables for CeAu 4 Zn 2 . The 4 d site of the calcium compound shows small mixed Zn/Au occupancy. The A Au 4 Zn 2 structures consist of three‐dimensional gold networks (272–286 pm Au–Au in CeAu 4 Zn 2 ), which are penetrated by linear infinite zinc chains (266 pm Zn–Zn in CeAu 4 Zn 2 ) that extend along the c axis. The calcium or rare earth atoms fill Au 12 cavities within the networks. Temperature dependent magnetic susceptibility measurements reveal Pauli paramagnetism for CaAu 4 Zn 2 and Curie‐Weiss paramagnetism for the cerium, praseodymium, and neodymium compound, respectively. No magnetic ordering was evident down to 2.5 K. The static intermediate‐valent compound Ce 2 RuZn 4 crystallizes with a superstructure of CeAu 4 Zn 2 ( klassengleiche subgroup P 4/ nmm ) with a different but fully ordered substitution on the transition metal sites. This structural relationship is discussed on the basis of a group‐subgroup scheme.