Growth and characterization of struvite-Na crystals

Sodium magnesium phosphate heptahyclraLe [NaMgPO4 center dot 7H(2)O], also known as struviLe-Na, is the sodium analog to struviLe. Among phosphate containing bio-minerals, struviLe has attracted considerable attention, because of its common occurrence in a wide variety of environments. Struvite and family crystals were found as urinary calculi in humans and animals. Struvite-Na crystals were grown by a single diffusion gel growth technique in a silica hydro gel medium. Struvite-Na crystals with different morphologies having transparent to translucent diaphaneity were grown with different growth parameters. The phenomenon of Liesegang rings was also observed with some particular growth parameters. The powder XRD study confirmed the structural similarity of the grown struvite-Na crystals with struvite and found that struvite-Na crystallized in the orthorhombic Pmn21 space group with unit cell parameters such as alpha = 6.893 angstrom, b= 6.124 angstrom, c=11.150 angstrom, and angstrom=13=7=90'. FT-IR spectra of struviteNa crystals revealed the presence of functional groups. The TGA, DTA and DSC were carried out simultaneously. The kinetic and thermodynamic parameters of dehydration/decomposition process were calculated. The variation of dielectric constant with frequency of applied field was studied in the range from 400 Hz to 100 kHz. (C) 2014 Elsevier B.V. All rights reserved.