Near-infrared spectroscopy to uranyl arsenates of the autunite and metaautunite group

A suite of uranyl arsenates have been analysed by near-infrared spectroscopy (NIR). The NIR spectra of zeunerite and metazeunerite in the first HOH fundamental overtone are different and the spectra of uranyl arsenates of different origins in the 6000-7500 cm−1 region are different. NIR spectroscopy provides a method of determination of the hydration of uranyl arsenates and has implications for the structure of water in the interlayer. Such a conclusion is also supported by the water OH stretching region where considerable differences are observed. NIR is an excellent technique for the study of the autunite minerals and may be used to distinguish between different autunite phases such as the partially dehydrated autunites for example zeunerite and metazeunerite.