Theoretical study of the decomposition mechanism of a series of group III triazides X(N3)3 (X = B, Al, Ga)

Density functional theory method is used to examine a series of group III triazides X(N3)3 (X = B, Al, Ga). These compounds, except for the C3h planar B(N3)3 and Al(N3)3, are first reported here. C3h planar structures are the most energetically favored for all singlet X(N3)3 systems. Potential‐energy surfaces for unimolecular decompositions of the C3h and CS planar X(N3)3 species have been investigated. Results show that decomposition of B(N3)3 obeys sequential fashion and follows a four‐step mechanism: (1) B(N3)3 → NB(N3)2 + N2; (2) NB(N3)2 → cyc‐N2BN3 + N2; (3) cyc‐N2BN3 → trigonal‐BN3 + N2; (4) trigonal‐BN3 → linear‐NBNN. Decomposition of Al(N3)3 follows a two‐step mechanism: (1) Al(N3)3 → NAl(N3)2 + N2; (2) NAl(N3)2 → linear‐AlN3 + 2N2. The dissociation of Ga(N3)3 follows only one‐step mechanism: Ga(N3)3 → angular‐GaN3 + 3N2. These findings may be helpful in understanding the decomposition mechanisms of group III triazides as well as the possible mechanism for XN film generation. © 2014 Wiley Periodicals, Inc. In addition to being candidates for high energy density materials, group III azides are useful precursors for the formation of nitrides, which have potential applications in microelectronic or optoelectronic devices. Computational results show that the decomposition of B(N3)3 follows a four‐step mechanism while Al(N3)3 decomposes with a two‐step mechanism. However, the dissociation of Ga(N3)3 is a one‐step reaction.