Germanium occurrence

Occurrence. Germanium is widely dispersed, but only a few minerals have been isolated. Germanite Cu3(Ge,Fe)S4 and renierite (Cu,Fe,Ge,Zn,As)S were in the past the principal sources of germanium. Actually germanium is recovered as by-product of the zinc production. 

Let me try to rephrase the argument. We assume that the combination of a finite number of fundamental properties, via a combinatorial approach, leads to a discrete set of macroscopic physical possibilities. We also know empirically that the chemical elements occur in a discrete manner because there are no intermediate elements between, say, hydrogen and helium. The combinatorial approach can thus be taken as an explanation for the discreteness in the occurrence of elements and furthermore it justifies the fact that Mendeleev regarded the yet undiscovered elements like germanium as being physical possibilities rather than merely logical ones. 

This circular reviews the occurrence of 34 trace elements in coal and the occurrence and distribution of chlorine, phosphorus, titanium, and manganese, which are not considered rare in coal. Separate chapters are devoted to germanium, gallium, and uranium in coal. 

Jhe distribution of beryllium, boron, titanium, vanadium, chromium, cobalt, nickel, copper, zinc, gallium, germanium, tin, molybdenum, yttrium, and lanthanum in the principal coal-producing beds of the Interior Province has been studied by the U. S. Geological Survey. Data, methods of sampling, and analyses are discussed by Zubovic and others (II, 12). This chapter discusses the occurrence of 13 of these elements with respect to geological and geochemical environments of coal deposition and chemical properties of the elements. Zinc and tin are not included in this study because they were detected in only a few samples. 

Rosenberg, E. 2008. Germanium Environmental occurrence, importance and speciation. Rev. Environ. Sci. Bio/Technol. in print (doi 10.1007/slll57-008-9143-x). 

The accurate determination of rate constants for the reactions of 19F atoms is often hampered by the presence of reactive F2 and by the occurrence of side reactions. The measurement of the absolute concentration of F atoms is sometimes a further problem. The use of thermal-ized 18F atoms is not subject to these handicaps, and reliable and accurate results for abstraction and addition reactions are obtained. The studies of the reactions of 18F atoms with organometallic compounds are unique, inasmuch as such experiments have not been performed with 19F atoms. In the case of addition reactions, the fate of the excited intermediate radical can be studied by pressure-dependent measurements. The non-RRKM behavior of tetraallyltin and -germanium compounds is very interesting inasmuch as not many other examples are known. The next phase in the 18F experiment should be the determination of Arrhenius parameters for selected reactions, i.e., those occurring in the earth s atmosphere, since it is expected that the results will be more precise than those obtained with 19F atoms. 

Occurrence. — Germanium is a very rare element, found in only a few minerals. It is usually found in nature as the sulfide and is very commonly associated with Hilver hi il fide. The principal ore is argyrodite, containing 6.93 per cent germanium. This ore comes from a Freiliorg, Saxony, mino and is very similar to canfieldite, 6.55 per cent germanium, found in... 

Francois et al. (1990) investigated the occurrence of the CeNiSi2 type for lanthanum-iron-germanium combinations from the alloys annealed at 1173K (LaFeo.60-o,69Ge2 a = 0.4347-0.4359, b= 1.683-1.679, c = 0.4210-0.4225). 

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