TY - JOUR
T1 - Thermodynamics of Ternary Nitride Formation by Ammonolysis
T2 - Application to LiMoN2, Na3WN3, and Na3WO3N
AU - Elder, S. H.
AU - DiSalvo, F. J.
AU - Topor, L.
AU - Navrotsky, A.
N1 - Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 1993
Y1 - 1993
N2 - An approximate method for predicting the feasibility of synthesis of ternary nitrides from appropriate oxides and ammonia gas is outlined. The known thermodynamic data for binary oxides and nitrides may be a helpful guide in predicting the formation of ternary nitrides by ammonolysis of ternary oxides. When the difference between the free energy of formation of the ternaries from the binary oxides (ΔGfb(O)) and binary nitrides (ΔGfb(N)) is small, the predictions are expected to be reliable. Such considerations suggest that ternary oxides containing the most electropositive metals (alkaline, alkaline earth, rare earth) will not form ternary nitrides by ammonolysis but perhaps will form oxynitrides or decompose to the electropositive metal oxide/hydroxide and binary transition-metal nitride. When the metals in the ternary oxide are from group V or greater, ternary nitride formation by reaction with ammonia is likely. We have developed a new high-temperature calorimetric procedure for determining the standard enthalpies of formation of ternary nitrides and applied it to: LiMoN2, Na3WN3, and Na3WO3N. The standard enthalpies of formation: ΔHfo(LiMoN2) = −386.0 ± 6.4 kJ/mol, ΔHfo(Na3WN3) = −358.7 ± 53.3 kJ/mol and ΔHfo(Na3WO3N) = −1358.8 ± 18.2 kJ/mol were obtained. An approximate method for predicting the feasibility of synthesis of ternary nitrides from appropriate oxides and ammonia gas is outlined. The known thermodynamic data for binary oxides and nitrides may be a helpful guide in predicting the formation of ternary nitrides by ammonolysis of ternary oxides. When the difference between the free energy of formation of the ternaries from the binary oxides (ΔGfb(O)) and binary nitrides (ΔGfb(N)) is small, the predictions are expected to be reliable. Such considerations suggest that ternary oxides containing the most electropositive metals (alkaline, alkaline earth, rare earth) will not form ternary nitrides by ammonolysis but perhaps will form oxynitrides or decompose to the electropositive metal oxide/hydroxide and binary transition-metal nitride. When the metals in the ternary oxide are from group V or greater, ternary nitride formation by reaction with ammonia is likely. We have developed a new high-temperature calorimetric procedure for determining the standard enthalpies of formation of ternary nitrides and applied it to: LiMoN2, Na3WN3, and Na3WO3N. The standard enthalpies of formation: ΔHfo(LiMoN2) = −386.0 ± 6.4 kJ/mol, ΔHfo(Na3WN3) = −358.7 ± 53.3 kJ/mol and ΔHfo(Na3WO3N) = −1358.8 ± 18.2 kJ/mol were obtained.
AB - An approximate method for predicting the feasibility of synthesis of ternary nitrides from appropriate oxides and ammonia gas is outlined. The known thermodynamic data for binary oxides and nitrides may be a helpful guide in predicting the formation of ternary nitrides by ammonolysis of ternary oxides. When the difference between the free energy of formation of the ternaries from the binary oxides (ΔGfb(O)) and binary nitrides (ΔGfb(N)) is small, the predictions are expected to be reliable. Such considerations suggest that ternary oxides containing the most electropositive metals (alkaline, alkaline earth, rare earth) will not form ternary nitrides by ammonolysis but perhaps will form oxynitrides or decompose to the electropositive metal oxide/hydroxide and binary transition-metal nitride. When the metals in the ternary oxide are from group V or greater, ternary nitride formation by reaction with ammonia is likely. We have developed a new high-temperature calorimetric procedure for determining the standard enthalpies of formation of ternary nitrides and applied it to: LiMoN2, Na3WN3, and Na3WO3N. The standard enthalpies of formation: ΔHfo(LiMoN2) = −386.0 ± 6.4 kJ/mol, ΔHfo(Na3WN3) = −358.7 ± 53.3 kJ/mol and ΔHfo(Na3WO3N) = −1358.8 ± 18.2 kJ/mol were obtained. An approximate method for predicting the feasibility of synthesis of ternary nitrides from appropriate oxides and ammonia gas is outlined. The known thermodynamic data for binary oxides and nitrides may be a helpful guide in predicting the formation of ternary nitrides by ammonolysis of ternary oxides. When the difference between the free energy of formation of the ternaries from the binary oxides (ΔGfb(O)) and binary nitrides (ΔGfb(N)) is small, the predictions are expected to be reliable. Such considerations suggest that ternary oxides containing the most electropositive metals (alkaline, alkaline earth, rare earth) will not form ternary nitrides by ammonolysis but perhaps will form oxynitrides or decompose to the electropositive metal oxide/hydroxide and binary transition-metal nitride. When the metals in the ternary oxide are from group V or greater, ternary nitride formation by reaction with ammonia is likely. We have developed a new high-temperature calorimetric procedure for determining the standard enthalpies of formation of ternary nitrides and applied it to: LiMoN2, Na3WN3, and Na3WO3N. The standard enthalpies of formation: ΔHfo(LiMoN2) = −386.0 ± 6.4 kJ/mol, ΔHfo(Na3WN3) = −358.7 ± 53.3 kJ/mol and ΔHfo(Na3WO3N) = −1358.8 ± 18.2 kJ/mol were obtained.
UR - http://www.scopus.com/inward/record.url?scp=0001177362&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0001177362&partnerID=8YFLogxK
U2 - 10.1021/cm00034a027
DO - 10.1021/cm00034a027
M3 - Article
AN - SCOPUS:0001177362
SN - 0897-4756
VL - 5
SP - 1545
EP - 1553
JO - Chemistry of Materials
JF - Chemistry of Materials
IS - 10
ER -