This invention is based on the preparation of new solid acid triphosphates
with compositions of the general formula M(IV)(HPO4)(H2PO4)2, where M(IV)
is a tetravalent metal or a mixture of tetravalent metals. These
compounds are insoluble in water the greater part of most organic
solvents. They show a high non-water assisted protonic conductivity
(about 0.01-0.04 S/cm at 100.degree. C. and a relative humidity lower
than 1%). These compounds can be used as proton conduction separators in
electrochemical devices, to operate at low relative humidity values, as
for example in different fuel cells, protonic pumps for electrochemical
hydrogenation and dehydrogenation of organic compounds, or for hydrogen
production from hydrogenated organic compounds by electro-reforming, or
also for removing hydrogen from equilibrium reactions. These compounds
can also be used in electrochemical sensors, in super capacitors and as
acid catalysts in non-aqueous or anhydrous gaseous phases.