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Syntheses and Structures of the Germanides CaNiGe and MgCoGe as well as Chemical Bonding in CaNiGe and CaNi 2 Ge 2
Author(s) -
Hlukhyy Viktor,
Chumalo Nataliya,
Zaremba Vasyl',
Fässler Thomas F
Publication year - 2008
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.200700534
Subject(s) - intermetallic , tantalum , germanium , crystallography , chemical bond , chemistry , crystal structure , germanide , magnesium , materials science , metallurgy , silicon , organic chemistry , alloy
The intermetallic germanides CaNiGe and MgCoGe have been synthesized from the elements in sealed tantalum tubes in a high‐frequency furnace. The compounds were investigated by X‐ray diffractions both on powders and single crystals: CeFeSi structure type, P 4/ nmm , a = 4.19341(3), c = 6.6264(1) Å, w R2 = 0.030, 124 F 2 values, 10 variable parameters for CaNiGe and a = 3.8960(4), b = 6.1929(11) Å, w R2 = 0.048, 104 F 2 values, 10 variable parameters for MgCoGe. In CaNiGe and MgCoGe the transition metal and germanium atoms build [ T Ge] layers ( T = Ni, Co), which are separated by the calcium and magnesium atoms, respectively. The crystal structures of CaNiGe and MgCoGe as well as chemical bonding in CaNiGe and CaNi 2 Ge 2 are discussed in terms of LMTO bond structure calculation and analysis using the Electron Localization Function (ELF). The Ge–Ge bond formation in polyanionic $^{3}_{\infty}\rm [NiGe]^{-}$ network of CaNi 2 Ge 2 can formally be regarded as oxidative coupling product of $^{2}_{\infty}\rm [NiGe]^{2-}$ layers of CaNiGe.