Germanides

Alloys. Many Ge alloys have been prepared and studied. Most have been made by melting Ge with another metal, much as germanides are made. Collections of binary phase diagrams and comments about many Ge alloys are available (25—28). 

G. V. Samsonov and V. N. Bondarev, Germanides trans. A. Wald, Primary Sources, New York, 1970. 

Reactions of HCl and nitrides, borides, silicides, germanides, carbides, and sulfides take place at significant rates only at elevated (>650° C) temperatures. The products are the metal chlorides and the corresponding hydrides. The reactions most studied are those involving nitrides of aluminum, magnesium, calcium, and titanium, where ammonia (qv) is formed along with the corresponding metal chloride. 

Niobium germanide, NbgGe, is a superconductor with a high transition temperature (T, = 20K). It is prepared by CVD by the coreduction of the chlorides as follows ... 

Compounds isotypic with the k phases arc found among intcrmetallics, borides, carbides and oxides and also with silicides, germanides, arsenides, sulfides and sclcnides no nitrides, however, are found. The mode of filling the various voids in the metal host lattice of the k phases follows the schemein Ref. 4 and is presented in Table 1 for all those compounds for which the atom distribution is well known from x-ray or neutron diffraction. Accordingly, B atoms in tc-borides, Zr, Mo, W, Re)4B and Hfy(Mo, W, Re, Os)4B , occupy the trigonal prismatic interstices within the parent metal framework of a Mn, Aln,-type structure (see Table 1 see also ref. 48). Extended solid solutions are found for (Hf, Al)[Pg.140]

The binary alloy is pyrophoric and may ignite in contact with water, as do other alkali metal germanides. 

Similar trends are observed for other members of the series, such as lithium silanides and germanides where consistently shorter Li-Ge bonds than Li-Si are observed.213 Similarly, heavy alkaline earth metal silanides and germanides display the same trend - slightly shorter M-Ge bonds than M-Si distances.218-220... 

In analogy to the corresponding silanides Si(SiMe3)3 and germanides Ge(SiMe3)3 , the lithium and sodium... 

Synthesis in liquidAl Al as a reactive solvent Several intermetallic alu-minides have been prepared from liquid aluminium very often the separation of the compounds may be achieved through the dissolution of Al which dissolves readily in several non-oxidizing acids (for instance HC1). For a review on the reactions carried out in liquid aluminium and on several compounds prepared, see Kanatzidis et al. (2005) binary compounds are listed (Re-Al, Co-Al, Ir-Al) as well as ternary phases (lanthanide and actinide-transition metal aluminides). Examples of quaternary compounds (alumino-silicides, alumino-germanides of lanthanides and transition metals) have also been described. As an example, a few preparative details of specific compounds are reported in the following. 

Silicides and Germanides The electrolysis of melts containing Na2SiF6 (or Na2Ge20s) and transition metal (Cr, Mn, Fe, Ni, etc.) oxides or fluorides often resulted in the synthesis of the silicides (or germanides). 

Binary representatives of this structure are found among the Mn, Cr, Fe, Ru, Rh, Os monosilicides and germanides, Zr and Hf monoantimonides, AuBe and A1 (or Ga) compounds with Pd and Pt. Ternary phases such as CrMnSi2, CrFeSi2, CrCoSi2, FeMnSi2 have been described. 

Ternary germanides LnAgGe (Ln = Y, Sm, Gd-Lu) with an ordered Fe2P-type structure have been described by Gibson et al. (1996). 

Figure 7.45. Rare earth germanides. Summary (according to Venturini el al. 1999a,b,c) of the crystal-chemistry of RGcx phases in the composition range RGej 5 to =RGel s. The stoichiometries observed in the various compounds of the different R, are shown as a function of the R atomic dimensions (ionic radius of R3+). Notice (for x 1.625) the separation line between the two structural types the aThSi2-derivative types and the AlB2-derivative types.

Sodium-antimony alloy, 4797 Sodium germanide, 4418 Sodium-zinc alloy, 4798 Titanium-zirconium alloys, 4921 See also LANTHANIDE-TRANSITION METAL ALLOY HYDRIDES... 

Dennis und Skow (71) erhielten durch Zersetzen von Natrium-germanid mit Wasser einen dunkelbraunen Korper, fiir welchen sie die Formel (GeH)x vorschlagen. Die Struktur ist nicht bekannt. Beim Trocknen an der Luft zersetzt sich die Verbindung unter Explosion. Sie wirkt stark reduzierend und gibt mit Halogenen Germaniumhalogenide. 

Hohmann, E. Silicide und Germanide der Alkalimetalle. Z. anorg. Chem. 

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