Author Date

2026-04-27

Degree Name

Department

Chemistry and Biochemistry

College

Computational, Mathematical and Physical Sciences

Defense Date

2026-04-03

Publication Date

2026-04-27

First Faculty Advisor

Dr. Brian F. Woodfield

First Faculty Reader

Dr. Stacey J. Smith

Honors Coordinator

Dr. Brandon Gassaway

Keywords

Heat Capacity, Alkaline Earth Nitrides, Powder X-ray Diffraction, Entropy

Abstract

Alkaline earth nitrides are highly hygroscopic materials used in metal refinement and various synthetic processes. In this work, the low-temperature heat capacities of Mg₃N₂, Ca₃N₂, and Sr₃N₂ were measured for the first time. The Ca₃N₂ sample contained impurities, necessitating corrections to the heat capacity data. The absolute entropies of Mg₃N₂, Ca₃N₂, and Sr₃N₂ at 298.15 K were determined to be 75.1, 114.9, and 188.5 J∙K⁻¹∙mol⁻¹, respectively. Gibbs energies of formation were calculated for the two most common synthetic pathways: formation from the elements and formation from the metal and ammonia. These Gibbs energies had large, negative values between 100–1000 K. Because these reactions require high temperatures to proceed, we conclude that the activation energies are large. Calculated Gibbs energies of formation from the metal oxide and ammonia are large and positive between 100–1000 K, supporting the hypothesis that this reaction is unfavorable.