a b s t r a c t The silver acid salts Ag x H 3Àx PW 12 O 40 (Ag x WPA), where Ag content is x = 1 up to x = 2.5, were synthesized and characterized by Fourier transform infrared and micro-Raman spectroscopy, powder X-ray diffrac-tion and differential thermal and thermogravimetric analysis and nitrogen adsorption. The properties of the prepared salts are compared with those of the parent acid. Regarding the structural, textural and thermal and solubility characteristics, these salts are between salts of group A, with small metal ions, and B group salts with large metal ions. The acid salts are two phase mixtures of soluble acid and insol-uble neutral salt, like other alkaline acid salts of H 3 PW 12 O 40 for x < 2. The catalytic properties of the acid salts have been studied for the vapor-phase dehydration of ethanol, carried out in a conventional flow-type reactor at 300 °C. The acid salts exhibited stable catalytic activity, a little bit lower than tungsto-phosphoric acid for ethylene production from ethanol. Ó 2013 Elsevier B.V. All rights reserved.