Syntheses and structure of the La{sub 5}Ge{sub 3}Z phases (Z=Si, Sn, Pb, Ga, In): Structural relationships among the M{sub 5}X{sub 4}-type structures

Journal Article · Fri Apr 15 04:00:00 EDT 2005 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2005.01.021· OSTI ID:20725880

Guloy, Arnold ^[1]; Corbett, John D ^[1]

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1. Department of Chemistry and Ames Laboratory, Iowa State University, Ames, Iowa 50011 (United States)

The indicated reactions under arc-melting or high-temperature sintering conditions in Ta containers lead to (1) the apparent Zintl phase La{sub 5}Ge{sub 3}Si{sub 0.75}, stuffed Mn{sub 5}Si{sub 3}-type, P6{sub 3}/mcm from quenching; (2) {alpha}-La{sub 5}Ge{sub 3}Si (Sm{sub 5}Ge{sub 4}-type, Pnma); (3) {beta}-La{sub 5}Ge{sub 3}Si (Zr{sub 5}Si{sub 4}-type, P4{sub 1}2{sub 1}2) at high temperatures; (4) La{sub 5}Ge{sub 3}Tt, Tt=Sn, Pb, phases isotypic with 2); (5) the isotypic La{sub 5}Ge{sub 3}Tr, Tr=Ga, In (Gd{sub 5}Si{sub 4}-type, Pnma). The structures of compounds 3 and 5 (for Tr=Ga) have been refined from single crystal X-ray diffraction data. A general description of the three electron-poorer M{sub 5}X{sub 4} structure types 2,3,4 (and of Eu{sub 5}As{sub 4}-type (Cmca)) is given in terms of their common building block, an La{sub 9}Tt{sub 6} cubeoctahedra centered about the tightest bound La. Some electronic bonding effects are also generalized with regard to the dominance of extra free electrons beyond simple Zintl expectations.

• OSTI ID: 20725880
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 4 Vol. 178; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
GALLIUM COMPOUNDS
GERMANIDES
HEXAGONAL LATTICES
INDIUM COMPOUNDS
LANTHANUM COMPOUNDS
LEAD COMPOUNDS
MELTING
MONOCRYSTALS
ORTHORHOMBIC LATTICES
QUENCHING
SILICON COMPOUNDS
SINTERING
SYNTHESIS
TETRAGONAL LATTICES
TIN COMPOUNDS
X-RAY DIFFRACTION