The structure Of Cs2GeS2(OH)(2 center dot)yH(2)O in hydrous and anhydrous states has been investigated by means of neutron diffraction and infrared spectroscopy. This material belongs to a new class of intermediate temperature highly proton conducting alkali thio-hydroxogermanates. The results show that this material is amorphous, and that both the short and intermediate range structure of the hydrated and dehydrated states of the materials are largely the same. Moreover, the results point to a porous structure built up of thio-oxoanions and alkali ions. In the hydrated state, the waWr molecules appear to be confined to cages with a characteristic length of 7 angstrom. (C) 2006 Elsevier B.V. All rights reserved.