Thermodynamics of ternary nitride formation by ammonolysis: Application to LiMoN[sub 2], Na[sub 3]WN[sub 3], and Na[sub 3]WO[sub 3]N

Journal Article · Fri Oct 01 04:00:00 EDT 1993 · Chemistry of Materials; (United States)

DOI:https://doi.org/10.1021/cm00034a027· OSTI ID:5224392

Elder, S H; DiSalvo, F J ^[1]; Topor, L; Navrotsky, A ^[2]

---

1. Cornell Univ., Ithaca, NY (United States)
2. Princeton Univ., NJ (United States)

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 ([Delta]G[sub f][sup b](O)) and binary nitrides ([Delta]G[sub f][sup b](N)) is small, the predictions are expected to be reliable. Such considerations suggest that ternary oxides containing the most electropositve 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. The authors have developed a new high-temperature calorimetric procedure for determining the standard enthalpies of formation of ternary nitrides and applied it to: LiMoN[sub 2], Na[sub 3]WN[sub 3], and Na[sub 3]WO[sub 3]N. The standard enthalpies of formation: [Delta]H[sub f][degrees](LiMoN[sub 2]) = 386.0 [+-] 6.4 kJ/mol, [Delta]H[sub f][degrees] (Na[sub 3]WN[sub 3]) = [minus]358.7 [+-] 53.3 kJ/mol and [Delta]H[sub f][degrees] (Na[sub 3]WO[sub 3]N) = 1358.8 [+-] 18.2 kJ/mol were obtained. 41 refs., 1 fig., 7 tabs.

• OSTI ID: 5224392
• Journal Information: Chemistry of Materials; (United States), Journal Name: Chemistry of Materials; (United States) Vol. 5:10; ISSN CMATEX; ISSN 0897-4756
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALKALI METAL COMPOUNDS
CALORIMETRY
CHALCOGENIDES
CHEMICAL PREPARATION
ENTHALPY
FORMATION HEAT
LITHIUM COMPOUNDS
LITHIUM NITRIDES
MOLYBDENUM COMPOUNDS
MOLYBDENUM NITRIDES
NITRIDES
NITROGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
PNICTIDES
REACTION HEAT
REFRACTORY METAL COMPOUNDS
SODIUM COMPOUNDS
SODIUM NITRIDES
SODIUM OXIDES
SYNTHESIS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TUNGSTEN COMPOUNDS
TUNGSTEN NITRIDES
TUNGSTEN OXIDES