Pressure-induced disordering of sodium potassium sulfates and chromates

Bernardin, Frederick E.; Hammack, William S.

doi:10.1103/physrevb.54.7026

Cited by 13 publications

(7 citation statements)

References 27 publications

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“…The disorder induced by compression is reversible. Orientational disordering of tetrahedral units via compression has previously been observed in other materials, including K 2 CrO 4 , NaKSO 4 , and NaKCrO 4 , 59,60 and is to be expected when there is a change in volume associated with ordering-disordering.…”

Section: Phase Stability/metastabilitymentioning

confidence: 61%

Orientational order-dependent thermal expansion and compressibility of ZrW2O8 and ZrMo2O8

Gallington

Chapman

Morelock

et al. 2013

Phys. Chem. Chem. Phys.

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The role of MO4 (M = W, Mo) orientational disorder in the thermal expansion and compressibility of ZrW2O8 and ZrMo2O8 was investigated via in situ powder X-ray diffraction at elevated temperature and pressure. A dramatic reduction in the bulk modulus of α-ZrW2O8, which has ordered WO4 tetrahedra at room temperature, from 65 GPa at room temperature to 47 GPa at 386 K was observed to be concomitant with the onset of a reversible WO4 orientational disordering upon compression. Additionally, the coefficient of thermal expansion (CTE) of the α phase became more negative upon compression within the temperature range in which pressure-dependent disorder was observed; αl, over the range 298 to 386 K, was ~-11 ppm K(-1) at 35 MPa but ~-16 ppm K(-1) at 276 MPa. No softening upon heating or change in CTE upon compression was observed for ZrW2O8 above the order → disorder phase transition temperature. Cubic ZrMo2O8 has a disordered arrangement of MoO4 tetrahedra at all temperatures and pressures accessed in this study. Its bulk modulus was independent of temperature, and its CTE was insensitive to pressure, much like β-ZrW2O8. The stability/metastability of the cubic and orthorhombic phases upon heating above room temperature and compression is discussed, with a focus on changes in the thermodynamics and kinetics of the cubic ↔ orthorhombic transition.

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Section: Phase Stability/metastabilitymentioning

confidence: 61%

Orientational order-dependent thermal expansion and compressibility of ZrW2O8 and ZrMo2O8

Gallington

Chapman

Morelock

et al. 2013

Phys. Chem. Chem. Phys.

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“…The K 3 Na(CrO 4 ) 2 crystal belongs to the family of crystals of the general formula A 3 B(CX 4 ) 2 , where А, B are Li, K, Na, Rb, Cs, or NH 4 and С are the SO 4 , CrO 4 , or SeO 4 tetrahedra [1]. Many of the crystals from this family undergo the ferroelastic phase transition related with the CX 4 group ordering.…”

Section: Introductionmentioning

confidence: 99%

Acoustic studies of the ferroelastic phase transition in the K₃Na(CrO₄)₂ crystal

Charnaya¹,

Mróz

Раджабов

et al. 2003

Physica Status Solidi (b)

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PACS 62.20.Dc, 62.65.+k, 77.80.Bh Ultrasonic studies of the K 3 Na(CrO 4 ) 2 crystal were carried out within a temperature range of 185 to 295 K. Temperature dependences of the velocity and attenuation coefficient for the xx and zz longitudinal acoustic waves and the yx and zx transverse waves were measured. Noticeable anomalies in velocity and attenuation for transverse as well as for longitudinal waves were found near the ferroelastic phase transition which temperature was 235.5 K. The anomalies in the c 44 and c 66 elastic moduli were treated on the base of the Landau theory assuming the component ε 4 as the primary order parameter and (ε 2 -ε 1 )/2 as the secondary one. Six elastic moduli, c 11 , c 33 , c 44 , c 66 , c 12 , and c 14 were evaluated at room temperature.

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“…Thus, to obtain information about the structural phase transitions that occur in K 3 Na(CrO 4 ) 2 and K 3 Na(SeO 4 ) 2 , it is useful to measure their NMR spectra, the spin-lattice relaxation times, T 1 , and the spinspin relaxation times, T 2 , for their 23 Na and 39 K nuclei as functions of temperature. However, very little experimental investigation of K 3 Na(CrO 4 ) 2 and K 3 Na(SeO 4 ) 2 has been performed; only Raman scattering results for the ferroelastic phase transition [13], elastic constants [3,14], and electron paramagnetic resonance (EPR) measurements [15][16][17] have been reported.…”

Section: Introductionmentioning

confidence: 99%

A nuclear magnetic resonance study of the ferroelastic phase transitions of K₃Na(CrO₄)₂and K₃Na(SeO₄)₂single crystals

Lim¹

2008

J. Phys.: Condens. Matter

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Nuclear magnetic resonance (NMR) measurements were carried out for K3Na(CrO4)2 and K3Na(SeO4)2 crystals over a range of temperatures. Two and three groups were observed in the 23Na spectra of K3Na(CrO4)2 and K3Na(SeO4)2 crystals, respectively, which were found to become one group at the ferroelastic phase transition temperature, TC1. These transitions to one resonance line from two and three resonance lines are associated with the crystals’ ferroelastic phase transitions. The changes in the spin–lattice relaxation times, T1, for the 23Na and 39K nuclei in two crystals indicate that there is a structural phase transition from the trigonal phase to the monoclinic phase in these crystals at TC1. Further, our results for the shifts in the resonance frequencies for the 39K central resonance lines show that these ferroelastic phase transitions are accompanied by shifts of the two crystallographically independent K+ cations, and mainly affect the environment of K(2), which is the most loosely bound cation in the crystal structures. We conclude that shifts of the oxygen atoms in the chromate and selenate groups around the Na and K atoms also play important roles in these phase transitions. Therefore, the ferroelastic phase transitions in K3Na(CrO4)2 and K3Na(SeO4)2 crystals at TC1 = 239 K and TC1 = 334 K, respectively, are accompanied by slight changes in the respective geometries of the CrO4 and SeO4 tetrahedra around the Na and K atoms.

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Pressure-induced disordering of sodium potassium sulfates and chromates

Cited by 13 publications

References 27 publications

Orientational order-dependent thermal expansion and compressibility of ZrW2O8 and ZrMo2O8

Orientational order-dependent thermal expansion and compressibility of ZrW2O8 and ZrMo2O8

Acoustic studies of the ferroelastic phase transition in the K₃Na(CrO₄)₂ crystal

A nuclear magnetic resonance study of the ferroelastic phase transitions of K₃Na(CrO₄)₂and K₃Na(SeO₄)₂single crystals

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Pressure-induced disordering of sodium potassium sulfates and chromates

Cited by 13 publications

References 27 publications

Orientational order-dependent thermal expansion and compressibility of ZrW2O8 and ZrMo2O8

Orientational order-dependent thermal expansion and compressibility of ZrW2O8 and ZrMo2O8

Acoustic studies of the ferroelastic phase transition in the K3Na(CrO4)2 crystal

A nuclear magnetic resonance study of the ferroelastic phase transitions of K3Na(CrO4)2and K3Na(SeO4)2single crystals

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Product

Resources

About

Acoustic studies of the ferroelastic phase transition in the K₃Na(CrO₄)₂ crystal

A nuclear magnetic resonance study of the ferroelastic phase transitions of K₃Na(CrO₄)₂and K₃Na(SeO₄)₂single crystals