Growth, crystalline perfection and characterization of Hexaaquanickel(II) dipotassium tetrahydrogen tetra-o-phthalate tetrahydrate crystals

Pale-green single crystals of hexaaquanickel(II) dipotassium tetrahydrogen tetra-o-phthalate tetrahydrate K2[Ni(H2O)6] (C8H5O4)4·4H2O (PNHP), of dimension ∼33 mm × 18 mm × 4 mm have been grown by slow evaporation solution growth technique (SEST) and modified Sankaranarayanan–Ramasamy (SR) method. The powder XRD profiles and FT-IR are used for identifying the material. The lattice parameters of the as-grown crystals obtained by single crystal X-ray diffraction analysis confirm the formulae. Lower optical cut-off at ∼300 nm and optical transparency in the visible region were observed. The structural perfection of the grown crystal has been analyzed for SEST and SR method grown crystals by high-resolution X-ray diffraction (HRXRD) rocking curves (DC). The DCs of both the specimens are asymmetric with respect to Bragg position and more of scattered intensity in the negative direction is indicative of predominantly vacancy defects. Interestingly, SR method grown crystal has a better crystalline perfection than the conventionally grown crystal. The dielectric, thermal and mechanical behaviors of the specimen were also studied.

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► Bulk growth of large size phthalate complex crystals.
► Improvement of crystalline perfection by SR method.
► Good transferency and lower cut-off wavelength.