Structure Change in Strontium Oxide‐Doped Dicalcium Silicates

A series of strontium‐bearing dicalcium silicate (Ca 2 Si0 4 solid solutions (C 2 S( ss )), (Sr χ Ca 1‐χ ) 2 SiO 4 with 0.02 ≤χ≤ 0.10, was prepared and examined by powder X‐ray diffrac‐tometry. These crystals, heated in the stable‐temperature region of the α phase and then quenched in water, were composed of the β phase, with χ≤ 0.08, and the α' L and β phases, with χ= 0.10. With increasing x, the unit‐cell axes of the β phase expanded and the β angle became small with eventual increase in the unit‐cell volume. The Rietveld analysis of the β‐C 2 S( ss ) with χ= 0.08 showed that the Sr 2+ ions preferentially occupied the seven‐coordinated site rather than the eight‐coordinated site. This site preference, which was originally established in the parent α‐phase structure, seemed to cause the systematic change in the cell dimensions.