Physical Properties of Germanium

Germanium is a greyish white, brittle, lustrous metal which crystallises in the regular system; its density at 20° C. is 5.469, and it melts at 958° ± 5° C., and when saturated with oxide at 916° ± 5° C. According to Winkler the boiling-point of germanium is not much above its melting-point; Meyer and Mensching, however, have found little sign of volatility when the metal is heated to 1350° C. in an atmosphere of hydrogen or nitrogen; but in presence of some oxide, vapour is observed from 750° C. onwards.3 The specific heat was found by Nilson and Pettersson to vary somewhat with temperature as follows:

Temperature ° C.	0°-100°	0°-211°	0°-301.5°	0°-440°
Specific heat.	0.0737	0.0773	0.0768	0.0757
Atomic heat	5.34	5.59	5.55	5.47

The most intense lines in the spectrum of germanium are as follow:

Arc: 2592.64, 2651.28, 2651.69, 2691.45, 2709.70, 2754.69, 3039.22, 3269.62.

Spark: 2592.65, 2651.29, 2651.69, 2709.69, 2754.68, 3039.20, 4179.20, 4226.76.

Germanium dissolves in aqua regia, but not in hydrochloric acid, whilst towards nitric acid it behaves like tin, being converted into the dioxide. It is oxidised at high temperature, and combines directly with the halogens.