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Several New Phases in RE–Mg–Ge Systems (RE = Rare Earth Metal) – Syntheses, Structures, and Chemical Bonding
Author(s) -
Suen NianTzu,
Bobev Svilen
Publication year - 2012
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201200619
Subject(s) - chemistry , crystallography , crystal structure , rare earth , structure type , chemical bond , tin , germanium , metal , electronic structure , type (biology) , tetrahedron , mineralogy , computational chemistry , silicon , organic chemistry , ecology , biology
Reported are the synthesis and structural characterization of Ce 5 Mg 8 Ge 8 (its own structure type), CeMg 2– x Ge 2+ x (BaAl 4 ‐type structure), RE 4 Mg 7 Ge 6 (RE = Ce–Nd, Sm; La 4 Mg 7 Ge 6 ‐type structure), and RE 4 Mg 5 Ge 6 (RE = Ce, Pr; Tm 4 Zn 5 Ge 6 ‐type structure). The structures of these compounds have been established by single‐crystal and powder X‐ray diffraction. These compounds are closely related to each other not only in their chemical compositions but also in their structures. A common structural feature of all are MgGe 4 tetrahedra, which are connected by corner‐ and/or edge‐sharing into complex polyanionic frameworks with the rare‐earth metal atoms filling the “empty” space. The structures are compared to known types of structures, and we have investigated the chemical bonding in Ce 5 Mg 8 Ge 8 with electronic structure calculations, which were carried out by the tight‐bonding linear muffin‐tin orbital (TB–LMTO) method.