Thermal decomposition of iron(VI) oxides, K2FeO4 and BaFeO4, in an inert atmosphere

J. Madarász, Radek Zbořil, Z. Homonnay, Virender K. Sharma, G. Pokol

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

The thermal decomposition of solid samples of iron(VI) oxides, K2FeO4·0.088 H2O (1) and BaFeO4·0.25H2O (2) in inert atmosphere has been examined using simultaneous thermogravimetry and differential thermal analysis (TG/DTA), in combination with in situ analysis of the evolved gases by online coupled mass spectrometer (EGA-MS). The final decomposition products were characterized by 57Fe Mössbauer spectroscopy. Water molecules were released first, followed by a distinct decomposition step with endothermic DTA peak of 1 and 2 at 273 and 248 °C, respectively, corresponding to the evolution of molecular oxygen as confirmed by EGA-MS. The released amounts of O2 were determined as 0.42 and 0.52 mol pro formula of 1 and 2, respectively. The decomposition product of K2FeO4 at 250 °C was determined as Fe(III) species in the form of KFeO2. Formation of an amorphous mixture of superoxide, peroxide, and oxide of potassium may be other products of the thermal conversion of iron(VI) oxide 1 to account for less than expected released oxygen. The thermogravimetric and Mössbauer data suggest that barium iron perovskite with the intermediate valence state of iron (between III and IV) was the product of thermal decomposition of iron(VI) oxide 2.

Original languageEnglish
Pages (from-to)1426-1433
Number of pages8
JournalJournal of Solid State Chemistry
Volume179
Issue number5
DOIs
Publication statusPublished - May 2006

Fingerprint

inert atmosphere
Iron oxides
iron oxides
thermal decomposition
Pyrolysis
Decomposition
Differential thermal analysis
products
Iron
decomposition
thermal analysis
Molecular oxygen
Peroxides
Mass spectrometers
Barium
iron
Superoxides
Perovskite
Potassium
Thermogravimetric analysis

Keywords

  • BaFeO4
  • Differential thermal analysis (DTA)
  • Evolved gas analysis (EGA)
  • Iron(VI) oxides
  • KFeO
  • Mass spectroscopy (MS)
  • Mössbauer spectroscopy
  • O evolution
  • Thermogravimetry (TG)

ASJC Scopus subject areas

  • Inorganic Chemistry
  • Physical and Theoretical Chemistry
  • Materials Chemistry

Cite this

Thermal decomposition of iron(VI) oxides, K2FeO4 and BaFeO4, in an inert atmosphere. / Madarász, J.; Zbořil, Radek; Homonnay, Z.; Sharma, Virender K.; Pokol, G.

In: Journal of Solid State Chemistry, Vol. 179, No. 5, 05.2006, p. 1426-1433.

Research output: Contribution to journalArticle

@article{695b0144935a43ec987d635ff78de499,
title = "Thermal decomposition of iron(VI) oxides, K2FeO4 and BaFeO4, in an inert atmosphere",
abstract = "The thermal decomposition of solid samples of iron(VI) oxides, K2FeO4·0.088 H2O (1) and BaFeO4·0.25H2O (2) in inert atmosphere has been examined using simultaneous thermogravimetry and differential thermal analysis (TG/DTA), in combination with in situ analysis of the evolved gases by online coupled mass spectrometer (EGA-MS). The final decomposition products were characterized by 57Fe M{\"o}ssbauer spectroscopy. Water molecules were released first, followed by a distinct decomposition step with endothermic DTA peak of 1 and 2 at 273 and 248 °C, respectively, corresponding to the evolution of molecular oxygen as confirmed by EGA-MS. The released amounts of O2 were determined as 0.42 and 0.52 mol pro formula of 1 and 2, respectively. The decomposition product of K2FeO4 at 250 °C was determined as Fe(III) species in the form of KFeO2. Formation of an amorphous mixture of superoxide, peroxide, and oxide of potassium may be other products of the thermal conversion of iron(VI) oxide 1 to account for less than expected released oxygen. The thermogravimetric and M{\"o}ssbauer data suggest that barium iron perovskite with the intermediate valence state of iron (between III and IV) was the product of thermal decomposition of iron(VI) oxide 2.",
keywords = "BaFeO4, Differential thermal analysis (DTA), Evolved gas analysis (EGA), Iron(VI) oxides, KFeO, Mass spectroscopy (MS), M{\"o}ssbauer spectroscopy, O evolution, Thermogravimetry (TG)",
author = "J. Madar{\'a}sz and Radek Zbořil and Z. Homonnay and Sharma, {Virender K.} and G. Pokol",
year = "2006",
month = "5",
doi = "10.1016/j.jssc.2006.01.054",
language = "English",
volume = "179",
pages = "1426--1433",
journal = "Journal of Solid State Chemistry",
issn = "0022-4596",
publisher = "Academic Press Inc.",
number = "5",

}

TY - JOUR

T1 - Thermal decomposition of iron(VI) oxides, K2FeO4 and BaFeO4, in an inert atmosphere

AU - Madarász, J.

AU - Zbořil, Radek

AU - Homonnay, Z.

AU - Sharma, Virender K.

AU - Pokol, G.

PY - 2006/5

Y1 - 2006/5

N2 - The thermal decomposition of solid samples of iron(VI) oxides, K2FeO4·0.088 H2O (1) and BaFeO4·0.25H2O (2) in inert atmosphere has been examined using simultaneous thermogravimetry and differential thermal analysis (TG/DTA), in combination with in situ analysis of the evolved gases by online coupled mass spectrometer (EGA-MS). The final decomposition products were characterized by 57Fe Mössbauer spectroscopy. Water molecules were released first, followed by a distinct decomposition step with endothermic DTA peak of 1 and 2 at 273 and 248 °C, respectively, corresponding to the evolution of molecular oxygen as confirmed by EGA-MS. The released amounts of O2 were determined as 0.42 and 0.52 mol pro formula of 1 and 2, respectively. The decomposition product of K2FeO4 at 250 °C was determined as Fe(III) species in the form of KFeO2. Formation of an amorphous mixture of superoxide, peroxide, and oxide of potassium may be other products of the thermal conversion of iron(VI) oxide 1 to account for less than expected released oxygen. The thermogravimetric and Mössbauer data suggest that barium iron perovskite with the intermediate valence state of iron (between III and IV) was the product of thermal decomposition of iron(VI) oxide 2.

AB - The thermal decomposition of solid samples of iron(VI) oxides, K2FeO4·0.088 H2O (1) and BaFeO4·0.25H2O (2) in inert atmosphere has been examined using simultaneous thermogravimetry and differential thermal analysis (TG/DTA), in combination with in situ analysis of the evolved gases by online coupled mass spectrometer (EGA-MS). The final decomposition products were characterized by 57Fe Mössbauer spectroscopy. Water molecules were released first, followed by a distinct decomposition step with endothermic DTA peak of 1 and 2 at 273 and 248 °C, respectively, corresponding to the evolution of molecular oxygen as confirmed by EGA-MS. The released amounts of O2 were determined as 0.42 and 0.52 mol pro formula of 1 and 2, respectively. The decomposition product of K2FeO4 at 250 °C was determined as Fe(III) species in the form of KFeO2. Formation of an amorphous mixture of superoxide, peroxide, and oxide of potassium may be other products of the thermal conversion of iron(VI) oxide 1 to account for less than expected released oxygen. The thermogravimetric and Mössbauer data suggest that barium iron perovskite with the intermediate valence state of iron (between III and IV) was the product of thermal decomposition of iron(VI) oxide 2.

KW - BaFeO4

KW - Differential thermal analysis (DTA)

KW - Evolved gas analysis (EGA)

KW - Iron(VI) oxides

KW - KFeO

KW - Mass spectroscopy (MS)

KW - Mössbauer spectroscopy

KW - O evolution

KW - Thermogravimetry (TG)

UR - http://www.scopus.com/inward/record.url?scp=33646148742&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33646148742&partnerID=8YFLogxK

U2 - 10.1016/j.jssc.2006.01.054

DO - 10.1016/j.jssc.2006.01.054

M3 - Article

VL - 179

SP - 1426

EP - 1433

JO - Journal of Solid State Chemistry

JF - Journal of Solid State Chemistry

SN - 0022-4596

IS - 5

ER -