Variation of displacement parameters in structure refinements of low albite

摘要: New X-ray diffraction measurements of a well-ordered Roc Tourn6 low albite (space group Cl) were refined in variety models. In addition, structural data for other albites obtained from room-temperature and neutron refinements retrieved the literature. Comparison parameters indicates that highly significant differences exist among anisotropic displacement different sets Such are largely systematic analyzed terms -B"o values. Significant found between with sin d/)' cutoff ranges. Refinement models which Si Al scattering curves not correctly assigned lead to elToneous B"o Assumption nonrealistic vacancies on tetrahedral sites decreases B* values T but increases oxygen parameters. Choice ionic or neutral factors, selection weighting scheme, neglect anomalous dispersion correction (MoKa radiation) have only minor influence B".