Redetermination of the Atomic Weight of Germanium

A MAT 262 thermal ionization mass spectrometer was calibrated by using the gravimetric synthetic mixtures of highly enriched germanium isotopes in the form of oxides with known chemical purity.Measurements on natural germanium samples yielded an absolute isotopic composition of 20 37(5) at.% 70 Ge,27 38(4) at.% 72 Ge,7 76(5) at.% 73 Ge,36 66(5)at.% 74 Ge and 7 83(5)at.% 76 Ge,and the atomic weight of germanium as 72 639(4) both with an uncertainty given on the basis of 95% confidence limit.