Synthesis, structural, and spectral characterization of Keggin-type mono cobalt(II)-substituted phosphotungstate

Abstract

Keggin-type mono Co(II)-substituted phosphotungstate was synthesized from 12-tungstophosphoric acid and cobalt chloride tetrahydrate. The obtained complex was systematically characterized in solution as well as solid by various physicochemical techniques. A single-crystal X-ray analysis shows that the complex crystallizes in tetragonal system, P4₂/ncm space group with a = b = 20.9860(5) Å, c = 10.4368(3) Å, and Z = 4. The crystal showed two types of disorders related by center of symmetry. Structural studies did not show the presence of Co, but the incorporation of the metal ion was proved by various spectral techniques. Spectral as well as electrochemical studies confirmed the presence of Co(II) into the lacunary position of the phosphotungstate moiety.

Keywords:

• Keggin-type phosphotungstate
• Crystal structure
• Cobalt
• Electrochemistry

Acknowledgments

Ms P. Shringarpure and Mr K. Patel are thankful to Council of Scientific and Industrial Research (CSIR, New Delhi) and Department of Science and Technology (DST, SR/S1/IC-13/2007), New Delhi, for financial support. We are thankful to Mr Babulal Das, Chemistry Department, IIT, Guwahati, for recording single-crystal X-ray measurements as well as for data collection. We are also thankful to Ms Amrita Ghosh, CSMCRI, Bhavnagar, for carrying out electrochemical measurements.