Enthalpy of formation of Ln2O2CO3 II (Ln = La, Nd, Eu) and thermodynamics of decomposition equilibria

A. Olafsen Sjåstad; H. Fjellvåg; K. B. Helean; A. Navrotsky

doi:10.1016/j.tca.2012.09.036

Enthalpy of formation of Ln₂O₂CO₃ II (Ln = La, Nd, Eu) and thermodynamics of decomposition equilibria

A. Olafsen Sjåstad, H. Fjellvåg, K. B. Helean, A. Navrotsky

Research output: Contribution to journal › Article › peer-review

9 Scopus citations

Abstract

High temperature oxide melt solution calorimetry using molten 2PbO·B₂O₃ at 1078 K and molten 3Na ₂O·4MoO₃ at 976 K has been applied to determine standard enthalpies of formation, Δ_fH_m° (298 K), of Ln₂O₂CO₃ II (Ln = La, Nd, Eu) from their oxide components Ln₂O₃ and CO₂ at 298 K. Two solvents were applied to cross-check the thermodynamic cycles. Using molten 2PbO·B₂O₃, Δ_fH_m° (298 K) for La₂O₂CO₃ II, Nd₂O ₂CO₃ II and Eu₂O₂CO₃ II were found as -198.0 ± 1.7, -176.2 ± 3.1 and -151.4 ± 6.5 kJ mol^-1, respectively. Using molten 3Na₂O· 4MoO₃ the corresponding values for Nd₂O₂CO ₃ II and Eu₂O₂CO₃ II were determined as -176.6 ± 3.5 and -154.9 ± 3.2 kJ mol^-1, respectively. These enthalpies of formation are discussed in view of prior thermodynamic data, discrepancies are analyzed, and recommended values for enthalpy, entropy and free energy of formation for La₂O ₂CO₃ and Nd₂O₂CO₃ are given.

Original language	English (US)
Pages (from-to)	76-82
Number of pages	7
Journal	Thermochimica Acta
Volume	550
DOIs	https://doi.org/10.1016/j.tca.2012.09.036
State	Published - Dec 20 2012
Externally published	Yes

Keywords

Calorimetry
Enthalpy of formation
Rare earth oxide carbonate
Thermodynamic properties

ASJC Scopus subject areas

Instrumentation
Condensed Matter Physics
Physical and Theoretical Chemistry

Access to Document

10.1016/j.tca.2012.09.036

Cite this

@article{d7f17ec460684ba9b7b64db0e6645521,

title = "Enthalpy of formation of Ln2O2CO3 II (Ln = La, Nd, Eu) and thermodynamics of decomposition equilibria",

abstract = "High temperature oxide melt solution calorimetry using molten 2PbO·B2O3 at 1078 K and molten 3Na 2O·4MoO3 at 976 K has been applied to determine standard enthalpies of formation, ΔfHm° (298 K), of Ln2O2CO3 II (Ln = La, Nd, Eu) from their oxide components Ln2O3 and CO2 at 298 K. Two solvents were applied to cross-check the thermodynamic cycles. Using molten 2PbO·B2O3, ΔfHm° (298 K) for La2O2CO3 II, Nd2O 2CO3 II and Eu2O2CO3 II were found as -198.0 ± 1.7, -176.2 ± 3.1 and -151.4 ± 6.5 kJ mol-1, respectively. Using molten 3Na2O· 4MoO3 the corresponding values for Nd2O2CO 3 II and Eu2O2CO3 II were determined as -176.6 ± 3.5 and -154.9 ± 3.2 kJ mol-1, respectively. These enthalpies of formation are discussed in view of prior thermodynamic data, discrepancies are analyzed, and recommended values for enthalpy, entropy and free energy of formation for La2O 2CO3 and Nd2O2CO3 are given.",

keywords = "Calorimetry, Enthalpy of formation, Rare earth oxide carbonate, Thermodynamic properties",

author = "Sj{\aa}stad, {A. Olafsen} and H. Fjellv{\aa}g and Helean, {K. B.} and A. Navrotsky",

note = "Funding Information: A.O.S. is grateful to the Research Council of Norway for financial support. A.N. acknowledges support from the U.S. Department of Energy (Grant DE-FG02-03ER46053 ).",

year = "2012",

month = dec,

day = "20",

doi = "10.1016/j.tca.2012.09.036",

language = "English (US)",

volume = "550",

pages = "76--82",

journal = "Thermochimica Acta",

issn = "0040-6031",

publisher = "Elsevier",

}

TY - JOUR

T1 - Enthalpy of formation of Ln2O2CO3 II (Ln = La, Nd, Eu) and thermodynamics of decomposition equilibria

AU - Sjåstad, A. Olafsen

AU - Fjellvåg, H.

AU - Helean, K. B.

AU - Navrotsky, A.

N1 - Funding Information: A.O.S. is grateful to the Research Council of Norway for financial support. A.N. acknowledges support from the U.S. Department of Energy (Grant DE-FG02-03ER46053 ).

PY - 2012/12/20

Y1 - 2012/12/20

N2 - High temperature oxide melt solution calorimetry using molten 2PbO·B2O3 at 1078 K and molten 3Na 2O·4MoO3 at 976 K has been applied to determine standard enthalpies of formation, ΔfHm° (298 K), of Ln2O2CO3 II (Ln = La, Nd, Eu) from their oxide components Ln2O3 and CO2 at 298 K. Two solvents were applied to cross-check the thermodynamic cycles. Using molten 2PbO·B2O3, ΔfHm° (298 K) for La2O2CO3 II, Nd2O 2CO3 II and Eu2O2CO3 II were found as -198.0 ± 1.7, -176.2 ± 3.1 and -151.4 ± 6.5 kJ mol-1, respectively. Using molten 3Na2O· 4MoO3 the corresponding values for Nd2O2CO 3 II and Eu2O2CO3 II were determined as -176.6 ± 3.5 and -154.9 ± 3.2 kJ mol-1, respectively. These enthalpies of formation are discussed in view of prior thermodynamic data, discrepancies are analyzed, and recommended values for enthalpy, entropy and free energy of formation for La2O 2CO3 and Nd2O2CO3 are given.

AB - High temperature oxide melt solution calorimetry using molten 2PbO·B2O3 at 1078 K and molten 3Na 2O·4MoO3 at 976 K has been applied to determine standard enthalpies of formation, ΔfHm° (298 K), of Ln2O2CO3 II (Ln = La, Nd, Eu) from their oxide components Ln2O3 and CO2 at 298 K. Two solvents were applied to cross-check the thermodynamic cycles. Using molten 2PbO·B2O3, ΔfHm° (298 K) for La2O2CO3 II, Nd2O 2CO3 II and Eu2O2CO3 II were found as -198.0 ± 1.7, -176.2 ± 3.1 and -151.4 ± 6.5 kJ mol-1, respectively. Using molten 3Na2O· 4MoO3 the corresponding values for Nd2O2CO 3 II and Eu2O2CO3 II were determined as -176.6 ± 3.5 and -154.9 ± 3.2 kJ mol-1, respectively. These enthalpies of formation are discussed in view of prior thermodynamic data, discrepancies are analyzed, and recommended values for enthalpy, entropy and free energy of formation for La2O 2CO3 and Nd2O2CO3 are given.

KW - Calorimetry

KW - Enthalpy of formation

KW - Rare earth oxide carbonate

KW - Thermodynamic properties

UR - http://www.scopus.com/inward/record.url?scp=84868486270&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84868486270&partnerID=8YFLogxK

U2 - 10.1016/j.tca.2012.09.036

DO - 10.1016/j.tca.2012.09.036

M3 - Article

AN - SCOPUS:84868486270

SN - 0040-6031

VL - 550

SP - 76

EP - 82

JO - Thermochimica Acta

JF - Thermochimica Acta

ER -