Structural mechanisms of proton conduction in MemHn(XO4)(m + n)/2 crystals

Investigations of K₃H(SO₄)₂ samples, which belong to the family of Me _m H _n (XO₄)_{(m + n)/2} (Me = K, Cs, Rb, NH₄; X = S, Se, As) crystals, revealed temperature anomalies in the dielectric and optical properties and in the heat capacity upon phase transitions. X-ray diffraction studies confirmed that K₃H(SO₄)₂ crystals undergo a structural phase transition from the monoclinic phase to the trigonal phase C2/c → R m and that the high proton conductivity in the high-temperature phases of crystals belonging to this family is due to the formation of a qualitatively new system of hydrogen bonds. Original Russian Text ? A.A. Simonov, I.P. Makarova, V.V. Grebenev, 2009, published in Fizika Tverdogo Tela, 2009, Vol. 51, No. 8, pp. 1477–1479.