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LaRh 3 Ga 2 – Structure Determination from a Trilling
Author(s) -
Seidel Stefan,
Hoffmann RolfDieter,
Pöttgen Rainer
Publication year - 2015
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.201500059
Subject(s) - rhodium , crystallography , crystal structure , superstructure , gallium , diffraction , lanthanum , single crystal , chemistry , materials science , inorganic chemistry , physics , metallurgy , catalysis , biochemistry , optics , thermodynamics
The gallide LaRh 3 Ga 2 was obtained by arc‐melting of the elements and subsequent annealing of the product button in a high‐frequency furnace. The sample was studied by powder X‐ray diffraction and the structure was refined from single crystal data of a trilling: ErRh 3 Si 2 type (CaCu 5 superstructure), Imma , a = 760.1(2), b = 975.6(3), c = 564.0(2) pm, wR = 0.0358 for 717 F 2 values and 23 variables; domain ratio 0.36(1) / 0.28(1) / 0.35(1). The rhodium atoms build up Kagomé networks (281.8 and 282.2 pm Rh–Rh), which are condensed through the gallium atoms (249.6–251.0 pm Rh–Ga). The lanthanum atoms fill large voids left by the three‐dimensional [Rh 3 Ga 2 ] network. They have coordination number 18 (6 Ga + 12 Rh) in form of a hexa‐capped hexagonal prism. The crystal chemical relationship with the aristotype CaCu 5 is briefly discussed on the basis of a group‐subgroup scheme.