Solid State Communications 150 (2010) 386–388 Contents lists available at ScienceDirect Solid State Communications journal homepage: www.elsevier.com/locate/ssc Synthesis of BaSO 4 nanoparticles by precipitation method using sodium hexa metaphosphate as a stabilizer Asha Gupta a , Preetam Singh b , C. Shivakumara b,∗ a Materials Research Centre, Indian Institute of Science, Bangalore – 560 012, India b Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore – 560 012, India article info Article history: Received 25 October 2009 Received in revised form 24 November 2009 Accepted 25 November 2009 by R. Phillips Available online 1 December 2009 Keywords: A. Nanostructures B. Chemical synthesis C. Crystal structure and symmetry D. X-ray scattering abstract We describe the synthesis and structure of Barium sulfate nanoparticles by precipitation method in the presence of water soluble inorganic stabilizing agent, sodium hexametaphosphate, (NaPO 3 ) 6 . The structural parameters were refined by the Rietveld refinement method using powder X-ray diffraction data. Barium sulfate nanoparticles were crystallized in the orthorhombic structure with space group Pbnm (No. 62) having the lattice parameters a = 7.215(1)(Å), b = 8.949(1)(Å) and c = 5.501(1)(Å) respectively. Transmission electron microscopy study reveals that the nanoparticles are size range, 30–50 nm. Fourier transform infrared spectra showed distinct absorption due to the SO 2− 4 moiety at 1115 and 1084 cm −1 indicating formation of barium sulfate nanoparticles free from the phosphate group from the stabilizer used in the synthesis. © 2009 Elsevier Ltd. All rights reserved. 1. Introduction Barium sulfate, commonly referred to as barite, is used widely because of its high specific gravity, opaqueness to X-rays, inertness and whiteness. Barite is one of the most important fillers used in the plastics, rubber, lithographic ink, paint industries, linoleum, oil cloth and in pharmaceutical formulations [1] and has been used extensively for investigating several phenomena of the precipi- tation process, precursors mixing, crystal growth and morphol- ogy [2–7]. Recently, barite was incorporated into polymers to form electrical-insulating barite/epoxy composites with X-ray attenua- tion properties [8]. The synthesis of particles with nanometer size dimensions is of increasing scientific and technical interest. The small size of these particles endows them with unusual structural, electronic, optical, magnetic and chemical properties, leading to many important applications such as catalyst, electro-optical de- vices and precursor phases to advance ceramics [9–11]. It is still a challenge to prepare pure ultra fine particles by simple synthetic methods. The nanoparticles can easily aggregate into larger par- ticles because of high surface activity and high surface adsorp- tion during the preparation. Controlling the particle size during the preparation, avoiding the aggregation of particles during dry- ing and calcination and to re-disperse it in the medium are current ∗ Corresponding author. Tel.: +91 80 2293 2951; fax: +91 80 23601310. E-mail address: shiva@sscu.iisc.ernet.in (C. Shivakumara). topics in the field of nanomaterials [12–14]. In addition, the de- velopment of novel materials requires smaller sized particles and inorganic additive powders with good dispersing properties in wa- ter in order to form a stable suspension. Qi et al. [1] synthesized spherical and cubic BaSO 4 with a barite structure in Triton X-100/ N-hexanol/cyclohexane/water water-in-oil microemulsions con- taining (NH 4 ) 2 SO 4 and Ba(Ac) 2 , respectively. Jia et al. [15] syn- thesized nanosized BaSO 4 particles using a membrane reactor, in which Na 2 SO 4 solution permeated through the micropores of an ultra filtration (UF) membrane and gradually flowed into the BaCl 2 solution to control the saturation ratio, nucleation and growth rates. Recently Hari Bala et al. [2] synthesized BaSO 4 nanoparticles of 25–52 nm range using BaCl 2 , (NH 4 ) 2 SO 4 and ethanol–water so- lution at 200 ◦ C in one hour. In this paper we report, synthesis of BaSO 4 nanoparticles at room temperature employing water solu- ble sodium hexametaphosphate, (NaPO 3 ) 6 as a stabilizer. 2. Experimental 2.1. Synthesis BaSO 4 nanoparticles were synthesized at room temperature in the presence of water soluble inorganic stabilizing agent, sodium hexametaphosphate, (NaPO 3 ) 6 . In a typical synthesis, 10 g of sodium hexametaphosphate was dissolved in 80 ml of distilled H 2 O in a 250 ml beaker with constant stirring. Then, 10 ml of 1 M sodium sulfate (Na 2 SO 4 ) solution was added, followed by 0038-1098/$ – see front matter © 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.ssc.2009.11.039