Indexing of the Powder X-ray Diffraction Patterns and Precise Determination of the Crystal Structure of Ba₂SiO₄

Abstract

The indexing of powder X-ray diffraction patterns and the precise determination of lattice constants and atomic co-ordinates of the synthesized Ba₂SiO₄ were performed using the structure model of β-K₂SO₄. The atomic co-ordinates of each atom in Ba₂SiO₄ was determined by means of trial and error method with IBM 7040 computor.
The results obtained are summarized as follows:
Crystal system Orthorhombic
Lattice constants a=5.772Å, b=10.225Å, c=7.513Å
Space group D_2h¹⁶-P_mcn
Density D_cal.=5.472g/cm³, D_obs.=5.427g/cm³
Molecular number in unit cell z=4
Atomic co-ordinates
The reliability of the calculated intensities about the thirty peaks was 0.171 and the agreement of the thoretical density with observed value was satisfactory, which indicates the above-mentioned indices, lattice constants and atomic co-ordinates are appropriate.