Comparison of trigonal B2O3 structures with high and low space-group symmetry

The geometrical, energetic and electronic properties of the low-pressure trigonal phase of B2O3 are studied theoretically at density functional theory level. Different methods and types of basis sets are used and the corresponding results are compared for two previously proposed structures with space group symmetries P3121 and P31. Based on the comparison of calculated and experimental structure parameters, and the calculated lattice energies of the two structures, it is concluded that the ground-state structure of B2O3 has P3121 symmetry. This is in agreement with a recent analysis of the spectroscopic data.