Germanium melting point

Germanium(IV) oxide occurs in two forms one has a rutile lattice and melts at 1359 K whilst the other has a quartz lattice and a melting point of 1389 K. It can be prepared by oxidation of germanium using, for example, concentrated nitric acid, or by the hydrolysis of germanium tetrachloride ... 

As there are no suitable organometallic precursors commercially available, initial work dealt with the synthesis of such a precursor [4]. 2,5-Bis(rbutyl)-2,5-diaza-l-germa-cyclopentane is a monomeric solid with a melting point of 45 °C and a sufficient vapour pressure of 0.40 mbar at 40 °C to allow its introduction into the CVD reactor. For the details about the synthesis and properties of this precursor we refer to a recent paper [4]. The present work deals with the investigation of the thermal decomposition of the precursor, the deposition of amorphous germanium (a-Ge) and the characterization of the deposited thin films. Finally some data should try to give some understanding about the deposition mechanism. 

Silicon and germanium crystallize in the diamond structure. However, they have somewhat weaker covalent bonds than carbon as a consequence of less efficient orbital overlap. These weaker bonds result in lower melting points for silicon (1420°C for Si and 945°C for Ge, compared with 4100°C for diamond) and greater chemical reactivity. Both sihcon and germanium are semiconductors, described in Chapter 7. 

One possible explanation for these results and the observation that TCB did not wet the bare germanium disc is that it is the wetting properties of the molten polymer that are important and not that of TCB. The temperature of the surface of all discs used exceeded the melting points of all the polymers investigated for the entire experiment. Furthermore, with the evaporation conditions used for all experiments except the last one mentioned, evaporation of solvent was instantaneous when the droplets reached the disc surface. No liquid accumulation was evident. 

Phenylgermanic acid anhydride, (CgHsGeOjaO.—Equimolecular proportions of mercury diphenyl and germanium tetrachloride in dry xylene are heated in a sealed Pyrex bulb for two days, then diluted with dry ether and filtered. The solid residue is pure phenylmercuric chloride, and the filtrate is treated with benzene, and finally with water containing a few drops of ammonium hydroxide. The granular precipitate which separates at the liquid interface is removed and dried at 115° C. The anhydride is a white, fluffy, amorphous solid, with no definite melting-point, soluble in excess of alkali, and reprecipitated by carbon dioxide, insoluble in water and organic solvents. 

Germanium looks like a metal. It has a bright, shiny, silvery color. But it is britde and breaks apart rather easily, which metals normally do not do. It has a melting point of 1,719°F (937.4°C) and a boiling point of 5,130°F (2,830°C). It conducts an electric current poorly. Substances of this kind are called semiconductors, which conduct an electric current, but not nearly... 

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