Elastic, thermoelastic and piezoelectric properties of 11 new bis(alkylammonium) and bis(polyalkylammonium) zirconium bis(nitrilotriacetates)

摘要

Single crystals with dimensions up to 20 x 20 x 20 mm(3) of 11 new bis (alkylammonium) zirconium bis(nitrilotriacetates) have been grown from aqueous solutions. Their elastic and thermoelastic properties were derived from ultrasonic resonant frequencies of plane-parallel plates and their shift upon variation of temperature, respectively. All of these crystal species belong to the monoclinic or orthorhombic crystal systems. The majority possesses an acentric crystal structure giving rise to piezoelectric effects, which surmount the maximum longitudinal piezoelectric effect d(111) of alpha-quartz by a factor of two. The pyroelectric effect of two of these specimens is about three to four times larger than pi(sigma)(3) of tourmaline. In addition, the tensors of thermal expansion were determined. Owing to the dominating large size of the anion most physical properties of the salts with different cations behave quite similar. Branched or more globular alkylammonium cations generate a slightly larger mean elastic stiffness than unbranched cations.