Thermochemical properties of the Fe-analogue of cryolite, Na3FeF6

• Authors: Ivan Nerád , Eva Mikšíková
• Languages of publication: EN

Abstracts

EN

Relative enthalpies for low-and high-temperature modifications of Na3FeF6 and for the Na3FeF6 melt have been measured by drop calorimetry in the temperature range 723–1318 K. Enthalpy of modification transition at 920 K, δtransH(Na3FeF6, 920 K) = (19 ± 3) kJ mol−1 and enthalpy of fusion at the temperature of fusion 1255 K, δfusH(Na3FeF6, 1255 K) = (89 ± 3) kJ mol−1 have been determined from the experimental data. Following heat capacities were obtained for the crystalline phases and for the melt, respectively: C p(Na3FeF6, cr, α) = (294 ± 14) J (mol K)−1, for 723 = T/K ≤ 920, C p(Na3FeF6, cr, β) = (300 ± 11) J (mol K)−1 for 920 ≤ T/K = 1233 and C p(Na3FeF6, melt) = (275 ± 22) J (mol K)−1 for 1258 ≤ T/K ≤ 1318. The obtained enthalpies indicate that melting of Na3FeF6 proceeds through a continuous series of temperature dependent equilibrium states, likely associated with the production of a solid solution. [...]

Keywords

EN

Na3FeF6 ; enthalpy; heat capacity; calorimetry

• Publisher: De Gruyter Open
• Journal: Open Chemistry
• Year: 2007
• Volume: 5
• Issue: 2
• Pages: 508-515

Dates

published

1 - 6 - 2007

online

27 - 2 - 2007

Contributors

author

Ivan Nerád

• Institute of Inorganic Chemistry, Slovak Academy of Sciences, 845 36, Bratislava, Slovak Republic

author

Eva Mikšíková

• Institute of Inorganic Chemistry, Slovak Academy of Sciences, 845 36, Bratislava, Slovak Republic

References

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Identifiers

DOI

10.2478/s11532-007-0015-y