Activity-composition relations along the orthogermanate joins of the systems NiOZnOGeO2 and CoOZnOGeO2 at 1050°C have been determined from the phase diagrams and the location of conjugation lines between oxide and orthogermanate phases. In each system, a second distinct spinel phase near XZn2GeO4 = 0.5 is observed in addition to the terminal spinel and phenacite solid solution. The free energies of transformation from the spinel to the phenacite structure are estimated to be +23, +12.7, and -12.6 kcal/mole for Ni2GeO4, Co2GeO4, and Zn2GeO4, respectively.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Condensed Matter Physics
- Physical and Theoretical Chemistry
- Inorganic Chemistry
- Materials Chemistry