Calculation of structural characteristics of Cd_1–xCa_xO (x = 0–1)

Abstract

The structural characteristics of isovalent and isostructural CdO–CaO alloy system are studied from the viewpoint of crystallography. The relative atomic positions in the Cd_1–xCa_xO alloy lattice can be determined by the Cd(Ca)–O bond lengths, which slightly decrease with increasing Ca concentration. Equivalent cation sites and Cd(Ca)–O bond lengths demonstrate that Cd_1–xCa_xO (x = 0−1) alloys crystallise in cubic Fm–3m space group (rocksalt structure). Each cation site in the Cd_1–xCa_xO alloy lattice has the identical probability of occupying such site by Cd and Ca, leading to the equivalent cation sites in alloy structure. Our calculated lattice parameters, volume of unit cell and 2θ angles of (200) and (111) peaks in the X-ray diffraction pattern of Cd_1–xCa_xO (x = 0−1) alloys agree with experimental measurements, validating our current crystallographic viewpoint.

Keywords:

• Cd_1–xCa_xO alloys
• Crystallography
• Rocksalt structure
• Symmetry

Acknowledgements

Financial supports from the National Natural Science Foundation of China (grant nos. 51125009, 50872016 and 20973033) and the National Natural Science Foundation for Creative Research Group (grant no. 20921002) are acknowledged.