Pyroelectric, dielectric, piezoelectric, and elastic properties of trigonal guanidinium tetrafluoroborate, C(NH2)3BF4

Single crystals of guanidinium tetrafluoroborate of optical quality and dimensions up to 60 × 60 × 30 mm have been grown from aqueous solutions. They possess a distinct polar morphology of point symmetry group 3m and strong pyroelectric, piezoelectric, electrooptic and nonlinear optic effects similar to those observed in hexagonal guanidinium iodide.