Detection of elastic and electric conductivity anomalies in Potassium Sulphamate single crystal

Single crystals of potassium sulfamate are grown by the method of slow evaporation at constant temperature. AC electrical conductivity of potassium sulfamate is measured in the temperature range 300-430 K and in the frequency region between 100 Hz and 3 MHz along the a, b and c-axes. Complex impedance spectroscopy is used to investigate the frequency response of the electrical properties of the potassium sulfamate single crystal. Temperature variation of AC conductivity and dielectric measurements show a slope change around 345 K for both heating and cooling run and this anomaly is attributed as phase transition, which is well supported by the DSC measurements. Value of loss tangent in the temperature region 330-400 K is found to be very low. Activation energies for the conduction process are calculated along the a, b and c-axes.

Section: Introductionmentioning

confidence: 66%

Section: Introductionmentioning

confidence: 91%

Electrical conductivity and dielectric properties of potassium sulfamate single crystals

Kumar

Iype

Rajesh

et al. 2011

“…The dielectric behavior was also studied by Lenin et al [11]. Variation of elastic constant and dc electrical conductivity in potassium sulfamate crystal, one of the derivative compounds of sulfamic acid, showed anomalies near 350 K and further attributed as phase transition [12]. In this paper the dc electrical conductivity of sulfamic acid crystal is studied in the temperature range 300 -440 K along the principal axes.…”

Section: Introductionmentioning

confidence: 89%

Electrical conductivity of sulfamic acid single crystals

Kumar¹,

Varughese²,

Iype

et al. 2010

Self Cite

Single crystals of sulfamic acid have been grown by the method of slow evaporation at constant temperature. DC electrical conductivity was measured in the temperature range 300 -440 K along a, b and c-axes. Conductivity measurements show slope change near 330 K and 410 K. The slope change observed around 330 K may be attributed as due to a phase transition which has been well supported by the DSC and DTA measurements. Slope change observed around 410 K is attributed as the onset of the thermal decomcoposition as evidenced by TGA curve. TGA studies show the crystal is very stable up to 440 K. Activation energies for the conduction process are calculated for all measured crystallographic directions.

“…Moreover, it has been found that KNH 2 SO 3 and NaNH 2 SO 3 crystals undergo phase transitions at 437.9 K with a transition enthalpy ΔH of 4.9 kJ/mol and at 456.0 K with ΔH of 1.9 kJ/mol, respectively [3]. Recently, it has been reported by the measurements of DSC and elastic constants that the KNH 2 SO 3 crystal also undergoes another phase transition at 350 K [4].…”

Section: Introductionmentioning

confidence: 99%

Crystal structure and phase transition of single crystalline CsNH₂SO₃

Fukami

Kyan

Nakano

et al. 2011

Differential scanning calorimetry (DSC) and X-ray diffraction measurements have been performed on cesium sulfamate CsNH 2 SO 3 single crystal. Two distinct endothermic peaks in the DSC curves are observed at 330 and 436 K. It is pointed out that the peak at 330 K is attributed to the structural phase transition, and the other peak at 436 K is associated with the thermal decomposition of the crystal. The structures in room-and hightemperasture phases are determined, and the space group of the sample crystal is found to change from monoclinic P2 1 /c to orthorhombic Pnma. The structure of the room-temperature phase consists of two different types of N-H···O hydrogen bond, but in the high-temperature phase there is no specific hydrogen bond between the NSO 3 pseudo-tetrahera.