Raman spectroscopy of synthetic erythrite, partially dehydrated erythrite and hydrothermally synthesized dehydrated erythrite

The Raman spectra of the mono, di and octa (commonly known as the mineral erythrite) hydrates of cobalt(II) arsenate synthesized using hydrothermal techniques were obtained. The hydrates can be distinguished by their water hydroxyl stretching bands. Splitting of the AsO stretching vibrations is observed in the 77 K spectrum. The band at 852 cm−1 is assigned to the ν1 symmetric stretching vibration and the band at 790 cm−1 to the ν3 antisymmetric stretching vibration. The low‐wavenumber region was used to identify bands attributable to the ν4 and ν2 modes.