A Combined Experimental and Theoretical Study on the Formation of Crystalline Vanadium Nitride (VN) in Low Temperature through a Fully Solid-State Synthesis Route

Abstract

An efficient method of synthesis of the vanadium nitride (VN) at low temperature is evaluated, and a mechanism for the crystallization process is proposed in this paper. From the mixture of ammonium m-vanadate with guanidinium carbonate an intermediate, guanidinium m-vanadate (GmV), is produced. GmV decomposed and underwent interesting structural transformations with increasing temperatures. This process is studied by theoretical (periodic DFT calculations) and experimental (51V MAS NMR, XRD, FTIR, and elemental analysis) methods. It is proposed that GmV is first decomposed into reactive species, then through solid-state transformations it is converted into vanadium oxynitride (VOxN1–x) with varying stoichiometry, and, last, GmV transforms itself into crystalline NaCl-type structure vanadium nitride. The DFT calculations show that this transformation is energetically favorable, and the formation of a VOxN1–x solid solution is feasible.