Refractive index and lattice parameter prediction for garnets (A(3)B(2)C(3)X(12))

The validity of prediction methods for garnet lattice parameters was tested, and a modified model with best fit to a lattice parameter database with over 1000 garnet compositions was developed. The lattice parameter predictions were used in Shannon and Fischer's model to predict garnet refractive indices. The predictions were compared to refractive index measurements reported for 143 garnet compositions. After calibration of electron overlap factors used in the model, the average prediction error was 1.13%. Sources of error in the models are discussed, as well as applications of the predictive methods.