GROWTH, MICROHARDNESS AND DIELECTRIC BEHAVIOR OF NASBF4 AND NA2SBF5 CRYSTALS

Sodium fluoroantimonate single crystals of monoclinic NaSbF4 and ortho rhombic NaSbF5 of optical quality have been grown from saturated solut ion at constant temperature (305 K) by slow evaporation technique. The grown crystals were confirmed by chemical and X-rav analysis. Vickers microhardness measurements have been carried out on these crystals. T he hardness values of NaSbF4 and Na2SbF5 single crystals are about 1.2 GPa and 1.15 GPa respectively. The dielectric constant (epsilon') and dielectric loss (Tan delta) were determined as a function of frequenc y in the range from 100 Hz to 100 KHz at room temperature. It was foun d that both the dielectric constant and dielectric loss decrease with increase in frequency. The values of dielectric constant of NaSbF4 and Na2SbF5 at (100) orientation for 100 KHz are about 11.40 and 14.15 re spectively.