High-temperature phase transitions in K3H(SO4)2

Calum R I Chisholm; Sossina M. Haile

doi:10.1016/S0167-2738(01)00947-X

High-temperature phase transitions in K₃H(SO₄)₂

Calum R I Chisholm, Sossina M. Haile^*

^*Corresponding author for this work

Materials Science and Engineering

Research output: Contribution to journal › Conference article › peer-review

35 Scopus citations

Abstract

Two phase transitions in K₃H(SO₄)₂ were discovered in the temperature range 25-300°C. The transition temperatures for the mid and high-temperature phases are T_c = 190°C (ΔH = 17.0 kJ/mol) and T_c = 227°C (ΔH = 7.4 kJ/mol), respectively, for freshly heated samples. A slow decomposition process begins above 270°C. The conductivity of K₃H(SO₄)₂ in these phases (σ = 1.68 × 10^-3 at 198°C and 2.19 × 10^-2 Ω^-1 cm^-1 at 251°C) is comparable to that of other M₃H(XO₄)₂ compounds (M = Cs, NH₄, Rb and X = S, Se) in their superprotonic phases. The activation energy for proton transport in the highest temperature phase of K₃H(SO₄)₂ is 0.45 eV, a value slightly higher than in the related compounds. Despite the similarity between the electrical properties of K₃H(SO₄)₂ and other M₃H(XO₄)₂ compounds, the structural properties are quite distinct. Specifically, high-temperature X-ray powder diffraction measurements show that neither of the high-temperature phases of K₃H(SO₄)₂ is trigonal, indeed, the symmetry of the structure decreases at the first transition, in contrast to the superprotonic phases in other M₃H(XO₄)₂ compounds.

Original language	English (US)
Pages (from-to)	179-184
Number of pages	6
Journal	Solid State Ionics
Volume	145
Issue number	1-4
DOIs	https://doi.org/10.1016/S0167-2738(01)00947-X
State	Published - Dec 1 2001
Event	10th International Conference on Solid State (SSPC10) - Montpellier, France Duration: Sep 24 2000 → Sep 28 2000

Keywords

KH(SO)
RbH(SeO)
Superprotonic phase transitions

ASJC Scopus subject areas

Chemistry(all)
Materials Science(all)
Condensed Matter Physics

Access to Document

10.1016/S0167-2738(01)00947-X

Cite this

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title = "High-temperature phase transitions in K3H(SO4)2",

abstract = "Two phase transitions in K3H(SO4)2 were discovered in the temperature range 25-300°C. The transition temperatures for the mid and high-temperature phases are Tc = 190°C (ΔH = 17.0 kJ/mol) and Tc = 227°C (ΔH = 7.4 kJ/mol), respectively, for freshly heated samples. A slow decomposition process begins above 270°C. The conductivity of K3H(SO4)2 in these phases (σ = 1.68 × 10-3 at 198°C and 2.19 × 10-2 Ω-1 cm-1 at 251°C) is comparable to that of other M3H(XO4)2 compounds (M = Cs, NH4, Rb and X = S, Se) in their superprotonic phases. The activation energy for proton transport in the highest temperature phase of K3H(SO4)2 is 0.45 eV, a value slightly higher than in the related compounds. Despite the similarity between the electrical properties of K3H(SO4)2 and other M3H(XO4)2 compounds, the structural properties are quite distinct. Specifically, high-temperature X-ray powder diffraction measurements show that neither of the high-temperature phases of K3H(SO4)2 is trigonal, indeed, the symmetry of the structure decreases at the first transition, in contrast to the superprotonic phases in other M3H(XO4)2 compounds.",

keywords = "KH(SO), RbH(SeO), Superprotonic phase transitions",

author = "Chisholm, {Calum R I} and Haile, {Sossina M.}",

note = "Funding Information: The authors gratefully acknowledge the financial support of the National Science Foundation and the Irvine Foundation.; 10th International Conference on Solid State (SSPC10) ; Conference date: 24-09-2000 Through 28-09-2000",

year = "2001",

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doi = "10.1016/S0167-2738(01)00947-X",

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TY - JOUR

T1 - High-temperature phase transitions in K3H(SO4)2

AU - Chisholm, Calum R I

AU - Haile, Sossina M.

N1 - Funding Information: The authors gratefully acknowledge the financial support of the National Science Foundation and the Irvine Foundation.

PY - 2001/12/1

Y1 - 2001/12/1

N2 - Two phase transitions in K3H(SO4)2 were discovered in the temperature range 25-300°C. The transition temperatures for the mid and high-temperature phases are Tc = 190°C (ΔH = 17.0 kJ/mol) and Tc = 227°C (ΔH = 7.4 kJ/mol), respectively, for freshly heated samples. A slow decomposition process begins above 270°C. The conductivity of K3H(SO4)2 in these phases (σ = 1.68 × 10-3 at 198°C and 2.19 × 10-2 Ω-1 cm-1 at 251°C) is comparable to that of other M3H(XO4)2 compounds (M = Cs, NH4, Rb and X = S, Se) in their superprotonic phases. The activation energy for proton transport in the highest temperature phase of K3H(SO4)2 is 0.45 eV, a value slightly higher than in the related compounds. Despite the similarity between the electrical properties of K3H(SO4)2 and other M3H(XO4)2 compounds, the structural properties are quite distinct. Specifically, high-temperature X-ray powder diffraction measurements show that neither of the high-temperature phases of K3H(SO4)2 is trigonal, indeed, the symmetry of the structure decreases at the first transition, in contrast to the superprotonic phases in other M3H(XO4)2 compounds.

AB - Two phase transitions in K3H(SO4)2 were discovered in the temperature range 25-300°C. The transition temperatures for the mid and high-temperature phases are Tc = 190°C (ΔH = 17.0 kJ/mol) and Tc = 227°C (ΔH = 7.4 kJ/mol), respectively, for freshly heated samples. A slow decomposition process begins above 270°C. The conductivity of K3H(SO4)2 in these phases (σ = 1.68 × 10-3 at 198°C and 2.19 × 10-2 Ω-1 cm-1 at 251°C) is comparable to that of other M3H(XO4)2 compounds (M = Cs, NH4, Rb and X = S, Se) in their superprotonic phases. The activation energy for proton transport in the highest temperature phase of K3H(SO4)2 is 0.45 eV, a value slightly higher than in the related compounds. Despite the similarity between the electrical properties of K3H(SO4)2 and other M3H(XO4)2 compounds, the structural properties are quite distinct. Specifically, high-temperature X-ray powder diffraction measurements show that neither of the high-temperature phases of K3H(SO4)2 is trigonal, indeed, the symmetry of the structure decreases at the first transition, in contrast to the superprotonic phases in other M3H(XO4)2 compounds.

KW - KH(SO)

KW - RbH(SeO)

KW - Superprotonic phase transitions

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VL - 145

SP - 179

EP - 184

JO - Solid State Ionics

JF - Solid State Ionics

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T2 - 10th International Conference on Solid State (SSPC10)

Y2 - 24 September 2000 through 28 September 2000

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