Abstract: | Single crystals of LiH2PO3 and LiH2PO4, both of space group symmetry Pna21, with dimensions up to 40 mm were grown from aqueous solutions by controlled evaporation. Pyroelectric, dielectric, piezoelectric, elastic and thermoelastic properties were studied by standard methods. The static piezoelectric constants d333 exceed d111 of α-quartz by only a factor 2. The pyroectric effects reach 3 times and 7 times, respectively, that of tourmaline. The mean elastic stiffness of the phosphite is 13% smaller than that of the phosphate, a phenomenon also observed in the corresponding sodium and potassium salts. |