A vibrational study on a phase transition in tin(II) chloride dihydrate. The O–X stretchings (X=H or D)

Abstract
The vibrational spectra of SnCl2⋅2H2O and its partially deuterated compound were measured in the O–X stretching region for both ordered and disordered phases. In the ordered phase some unexpected bands were found. They are explained in terms of hydrogen ion positional disorder present in the crystal. The Raman spectrum of SnCl2⋅2H2O was resolved in the disordered phase and direct information about disorder in hydrogen positions was obtained.