Abstract
Germania (GeO2) is an interesting compound from a crystalchemical viewpoint because it is a dioxide exhibiting the two important structures: the rutile-type with six-coordinated cation and quartz-type with four-coordinated cation. The polymorphism in GeO2 under atmospheric pressure was first studied by Laubengayer and Morton (1932) and Sarver (1961). According to them, the rutile-type GeO2 is stable below 1050°C above which temperature it transforms slowly to the quartz-type which melts at 1116°C. The reverse process can only be completed in the presence of a mineralizer. Several investigations have questioned the transformation temperature. Shafer and Roy (1957) reported that it should be lowered to 1007° C under atmospheric pressure. This value was later verified by Robbins and Levin (1959), and Majumdar (1958) placed the transformation temperature at 1002°C.
