  Interest in inorganic ternary nitride materials has grown rapidly over the
past few decades, as their diversity of chemistries and structures make them
appealing for a variety of applications. Due to synthetic challenges posed by
the stability of N2, the number of predicted nitride compounds dwarfs those
that have been synthesized, offering a breadth of opportunity for exploration.
This review summarizes the fundamental properties and structural chemistry of
ternary nitrides, leveraging metastability and the impact of nitrogen chemical
potential. A discussion of prevalent defects, both detrimental and beneficial,
is followed by a survey of synthesis techniques and their interplay with
metastability. Throughout the review, we highlight applications (such as
solid-state lighting, electrochemical energy storage, and electronic devices)
in which ternary nitrides show particular promise.
