Energetics of Ternary Nitrides:  Li−Ca−Zn−N and Ca−Ta−N Systems

Abstract

High-temperature oxide melt drop solution calorimetry was used to study the energetics of ternary nitride formation. The standard enthalpies of formation of several binary and ternary nitrides were determined. These values in kJ mol -1 are ∆H f °(Li 3 N) ) -166.1 ( 4.8, ∆H f °(Ca 3 N 2 ) ) -439.7 ( 6.6, ∆H f °(Zn 3 N 2 ) ) -43.5 ( 4.1, ∆H f °(Ta 3 N 5 ) ) -849.7 ( 11.7, ∆H f °(Ca 2 ZnN 2 ) ) -378.9 ( 8.6, ∆H f °(Sr 2 ZnN 2 ) ) -385.6 ( 14.3, ∆H f °(LiCaN) ) -216.8 ( 10.8, ∆H f °(LiZnN) ) -137.5 ( 6.8, and ∆H f °(CaTaN 2 ) ) -643.8 ( 9.6. These enthalpies of formation are small in magnitude compared to analogous values for oxides. However, the enthalpies of formation of the ternaries from binary nitrides can be quite substantial, confirming significant energetic stabilization of ternary nitrides. The energetics of ternary nitride formation appears to be dominated by the acid/base character of the cations. A linear relationship was found between the enthalpies of formation of the ternaries from binary nitrides and the ionic potential ratio of the two cations.

Thermodynamics of Formation of Binary and Ternary Nitrides in the System Ce/Mn/N

“…A trend, also followed by Ce 2 MnN 3 , reflects that the energetics of ternary nitride formation are dominated by the acid/base character of the cations in the ternary, as it was previously demonstrated in several examples [10±13]. (a) reference [19], (b) reference [33], and (c) reference [12] ±67.7 ± 6.6 ±137.5 ± 6.8 49% [12] …”

Calorimetric determination of the enthalpy of formation of InN and comparison with AlN and GaN

“…[18][19][20][21][22]30 Subsequent oxidation of reduced molybdenum species returns the solvent to its initial oxidation state. The melt does not quench to a glass, so the entire batch was ground to a powder to homogenize it before loading into the calorimetric crucibles.…”

“…1 Being at the forefront of electronics materials research, they are prepared in the form of thin films, synthesized as nanocrystalline and/or amorphous materials and grown as single crystals. 15 Several studies were performed on the energetics of binary and ternary transition metal nitrides, [16][17][18][19][20][21] Si 3 N 4 and sialon systems, [22][23][24][25] the Zr-O-N, 26 Y-Zr-O-N, Ca-Zr-O-N, and Mg-Zr-O-N systems, 27 and nitridophosphate PON 28 and Li-Na-P-O-N glasses. However, the determination of thermochemical data, essential for understanding phase stability and growth issues, is often neglected.…”

“…Oxidative drop solution calorimetry in a molten salt solvent at high temperature has been shown to be a general method to determine the heat of formation of nitrides and oxynitrides. [17][18][19][20][21][22][23][24][25][26][27][28][29][30] Samples were characterized for phase purity, nitrogen and oxygen contents, and surface area by a number of analytical techniques. 29 Recently, we resolved a major discrepancy in the enthalpy of formation of GaN using oxidative drop solution calorimetry and well-characterized GaN samples.…”

Thermochemistry of the ZrO2–SrO System: From enthalpies of formation and heat capacities of the compounds to the phase diagram

“…Drop solution enthalpies (Δ H ds ) measured for the compounds Sr n+1 Zr n O 3n+1 (n = 3, 2, 1) are listed in Table . The thermochemical cycle used for calculation of enthalpy of formation from the constituent oxides at 298 K, the drop solution enthalpies for the end member oxides, monoclinic ZrO 2 and SrO, and the calculated enthalpies of formation from component oxides are listed together with the experimental uncertainties for the three compounds. The experimental uncertainty corresponds to two standard deviations of the mean of at least eight measurements.…”