High-Temperature Structural Phase Transition of K2SO4 and K2SeO4 Crystals Studied by X-Ray Diffraction

Chen, T.M.; Chen, R.H.

doi:10.1006/jssc.1994.1236

Cited by 10 publications

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“…Structural order and disorder mechanisms play a vital role during the phase transformation. K 2 SO 4 possesses a dynamic disorder structure so that its internal structure can be easily modified by thermal treatment conditions. − …”

Section: Resultsmentioning

confidence: 99%

“…It has three different crystalline phases such as α, β, γ K 2 SO 4 . Generally, β-K 2 SO 4 exists at room temperature, it changes to the α phase at high temperature, and the corresponding phase transformation temperature is 871 K. Furthermore, γ-K 2 SO 4 is referred to as the low temperature phase, and it occurs at 5 K. Several researchers have reported the crystal growth and their characterizations. , Followed by the crystal growth, quite a few authors have reported the phase transformation from the orthorhombic to the hexagonal mechanism of K 2 SO 4 crystal with respect to temperature. − Kabbany et al has investigated the reversible phase transformation occurring in K 2 SO 4 with respect to heating and cooling . To the best of our knowledge, there is no article found in the literature dealing with high pressure induced (static or dynamic) phase transformation of the test crystal of K 2 SO 4 .…”

Section: Introductionmentioning

confidence: 99%

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Switchable Phase Transformation (Orthorhombic–Hexagonal) of Potassium Sulfate Single Crystal at Ambient Temperature by Shock Waves

Sivakumar

Devi

Dhas³

et al. 2020

Crystal Growth & Design

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In this research article, the shock wave induced switchable phase transition (β to α and α to β) of potassium sulfate (K 2 SO 4 ) crystal is demonstrated. The test crystals are subjected to shock waves of one pulse and two pulses, respectively, and their crystallographic properties are compared with the control test sample. Fourier transform Raman spectroscopy (FT-Raman), ultraviolet−visible spectroscopy (UV−vis), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), and dielectric studies are performed to understand the reversible phase transformation of potassium sulfate crystal enabled by the impact of shock waves. The bulk grain resistance (R g ) and capacitance C g values of control K 2 SO 4 crystal, post first shock, and second shock at room temperature are observed to be 88 MΩ, 92 MΩ, and 88 MΩ and 84 pF, 23 pF, and 84 pF, respectively. The dielectric relaxation time (τ g ) reveals the fact that the phase reversal occurs after the second shock. The values of τ g for control K 2 SO 4 crystal, post first shock, and second shock are calculated to be 7.39, 2.10, and 7.39 ms, respectively. The crystallographic and analytical studies reveal that the sample β-K 2 SO 4 is transformed to α-K 2 SO 4 during the first shock pulse loaded condition, and it comes back to the phase of β-K 2 SO 4 as and when loaded with the second shock pulse.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Switchable Phase Transformation (Orthorhombic–Hexagonal) of Potassium Sulfate Single Crystal at Ambient Temperature by Shock Waves

Sivakumar

Devi

Dhas³

et al. 2020

Crystal Growth & Design

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“…Single crystals are usually destroyed by this process. Chen and Chen [17] reported that crystals of K 2 SO 4 burst into pieces as they were heated to 500 • C and they attributed this phenomena to the OH + 3 ions which reported by Arnold et…”

Section: Tablementioning

confidence: 87%

The solid state phase transformation of potassium sulfate

Anooz

Bertram

Klimm

2007

Solid State Communications

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Potassium sulfate single crystals that are grown from aqueous solutions lose upon the first heating up to 1% of mass that is assumed to be water. This mass loss occurs in the vicinity of the PT from orthorhombic to hexagonal K2SO4. Only in the first heating run of K2SO4 that has not yet released water, pretransitional thermal effects can be observed in the DTA curve. If K2SO4 crystals are grown from solutions containing 4 wt.% Cd, Cu, or Fe, only Cu or Fe can be incorporated significantly with concentrations of several 0.1%. The phase transformation temperature measured for such solid solutions depends on the heating rate. For pure K2SO4, the phase transformation temperature is independent on heating rate 581.3 deg. C and the enthalpy of transformation is (5.8+/-0.2) kJ/mol.Comment: 11 pages, 6 figures, 1 tabl

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“…They decay in the temperature region from 300 to 450 C. If K 2 SO 4 is crystallized above 40 C, the content of water in crystals can be minimized [8,14]. Therefore investigation of the effect of crystal growth temperature in comparison with different concentrations of Cd 2þ on this phenomena of K 2 SO 4 crystals will be considered in future studies.…”

Section: Article In Pressmentioning

confidence: 99%

Effect of on the growth and thermal properties of K2SO4 crystal

Anooz

Klimm

Schmidbauer

et al. 2008

Journal of Physics and Chemistry of Solids

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Single crystals of pure and Cd 2þ -doped potassium sulfate were grown from aqueous solutions by the slow evaporation technique. From nutrient solutions with a CdSO 4 concentration of 4 wt% crystals containing 0.014 wt% dopant concentration could be obtained. The X-ray diffraction patterns of powdered crystals confirmed their crystal structures for both cases. Thermal analysis of pure crystals shows that the a-b phase transformation peak around 580 1C is superimposed with spurious effects, while for Cd 2þ -doped crystals this is not the case. The thermal hysteresis of the phase transition is 8 K for undoped K 2 SO 4 and is reduced to 3.5 K for K 2 SO 4 :Cd 2þ . Compared to undoped crystals, the optical transmittance of Cd 2þ -doped crystals is higher. r

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High-Temperature Structural Phase Transition of K2SO4 and K2SeO4 Crystals Studied by X-Ray Diffraction

Cited by 10 publications

References 0 publications

Switchable Phase Transformation (Orthorhombic–Hexagonal) of Potassium Sulfate Single Crystal at Ambient Temperature by Shock Waves

Switchable Phase Transformation (Orthorhombic–Hexagonal) of Potassium Sulfate Single Crystal at Ambient Temperature by Shock Waves

The solid state phase transformation of potassium sulfate

Effect of on the growth and thermal properties of K2SO4 crystal

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