Reliability of the structural data for calcite and dolomite extracted from X-ray powder diffraction by Rietveld refinement

Abstract

In this study, diffraction data of calcite and dolomite were collected using a conventional Bragg–Brentano diffractometer, which is a convenient, low-cost, and highly popular in-house instrument, and their crystal structures were refined by the Rietveld method. The effects of different refinement models on the structural data for calcite and dolomite are discussed and assessed in detail by comparing the data with those in literature. The bond lengths and atomic coordinates of calcite and dolomite are significantly affected by the different refinement models, whereas the cell parameters are nearly unchanged. The variations in the bond lengths are caused by the deviation of the atomic coordinates from the expected values. The results indicate the feasibility of extracting high-quality structural data from a conventional Bragg–Brentano diffractometer when appropriate strategies are applied.