Various pyrophosphates are very useful as bioceramics; for instance, strontium pyrophosphate is one of the emerging forms of alkaline phosphate. Strontium pyrophosphate dihydrate (Sr 2 P 2 O 7 2H 2 O) nanoparticles were synthesized by the surfactant-mediated approach and characterized by different techniques. From the powder XRD study, the average crystallite size was evaluated by applying Scherrer's formula, which was found to be 33.57 nm. The average crystallite size and internal strain were also evaluated using Williamson-Hall (W-H) method. The FT-IR spectroscopy study confirmed the presence of symmetric and asymmetric stretching vibrations of P-O-P and PO 3 . The UV-NIR absorption spectroscopy over the spectral range of 210-1200 nm was employed, and the energy band gap was calculated from Tauc's plot which was found to be 4.9 eV. Thermogravimetric analysis (TGA) confirmed the presence of two water molecules in the sample. From TGA, it was found that the sample become anhydrous and on heating above 410-800°C, the sample remained almost stable with slight weight gain due to adsorption of purged gas. Various kinetic parameters and thermodynamic parameters were evaluated for dehydration process. *pds_2307@yahoo.co.in

Nickel pyrophosphate is very popular material having applications in energy storage devices as well as supercapacitors. In this study, a surfactant-mediated approach was adapted to synthesis nickel pyrophosphate nanoparticles. The prepared material was subjected to structural, optical, electrical and electrochemical property studies. Peak broadening in the powder XRD pattern confirmed the nanostructured nature and monoclinic structure of pure [Formula: see text]-Ni2P2O7 nanoparticle with unit cell parameters of [Formula: see text] Ǻ, [Formula: see text] Ǻ, [Formula: see text] Ǻ, [Formula: see text], [Formula: see text], [Formula: see text]. Pure [Formula: see text]-Ni2P2O7 samples calcined at 300∘C, 600∘C, 900∘C show monoclinic structure. The average crystallite size and the internal strain were evaluated using Scherrer’s formula and Williamson–Hall (W-H) respectively. The TEM analysis confirmed the particle size in the range of 5–10[Formula: see text]nm for Ni2P2O7. Presence of symmetric and asymmetric stretching vibrations of P–O–P and PO3 was determined by FT-IR spectroscopy. The spectral range of 210–1200[Formula: see text]nm was employed by the UV-NIR absorption spectroscopy, and the energy band gap calculated from Tauc’s plot is found to be 5.38[Formula: see text]eV for pure Ni2P2O7. The EDAX analysis confirmed the elemental composition. The TGA analysis reveals that the sample becomes anhydrous and remain stable beyond 600∘C. The higher dielectric constant observed for the sample is promising for semiconductor, DRAM memory devices and ceramic capacitors. The a.c. conductivity increases with increasing frequency and follows Jonscher’s Power law. On the basis of Jonscher parameters, small polaron QMT conduction model is prevailing. The cyclic voltammetry study was carried out to ascertain the application potential for supercapacitors.

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