Preparation and characterization of In(I)-β″-alumina

In(I)-β″-alumina has been prepared by ion exchange from Na-β″-alumina. It is stable on heating in air up to 400 °C. Its structure was determined by Rietveld analysis using high-resolution X-ray powder diffraction data [R-3m, a = 5.6044(1) Å, c = 34.4807(1) Å, Z = 3]. The coordination of In(I) in this material is asymmetric, as indicated by the distortion index for this cation, suggesting some stereochemical activity for the lone pair on the cation. However, the distortion is not as pronounced as that seen in the Ga(I) analogue.