The polymorphism of "R3TaO7" compounds, which were regarded to be stable phases as 3:1 compounds in the R2O3Ta2O5 system (R=rare earth), are discussed in terms of lattice energies, calculated by the Ewald method. The phase with higher crystal symmetry has the negatively smaller lattice energy, so that the phase with higher symmetry become less stable; Cmcm>C2221>Fd3m>Pm3m>Fm3m. This is in accordance with experimental observations.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics