Abstract
Single crystals of manganese malonate dihydrate have been grown by the controlled diffusion of ionic species in hydrosilica gel. The crystals are found to be antiferromagnetic and optically nonlinear. X-ray diffraction studies on single crystals showed that the compound crystallizes in the orthorhombic system with a non centrosymmetric space group Pca2(1). The unit cell parameters are a = 8.309 angstrom, b = 9.590 angstrom, c = 7.327 angstrom. The UV-vis spectrum indicates good transparency in the visible region. The optical band gap of the material was estimated using diffuse reflectance spectroscopy (DRS). The second harmonic generation (SHG) efficiency of the material, evaluated using Kurtz and Perry powder test, is comparable with that of standard KDP crystals. Electrical and dielectric properties of the material were investigated over wide frequency and temperature range. The optical nonlinearity and SHG efficiency are attributed to the molecular acentricity and intermolecular hydrogen bonding. Distinctive structural features inclusive of acentric space group, intermolecular hydrogen bonding and bridging through anti-syn and anti-anti malonate groups are accountable for the antiferromagnetism exhibited by the material. (C) 2012 Elsevier GmbH. All rights reserved.