Nitrogen is an important impurity in Czochralski grown silicon (Cz–Si) as it enhances oxygen precipitation through the formation of vacancy–nitrogen–oxygen clusters and in particular the [Formula: see text] complexes. Here, we employ density functional theory (DFT) to predict the structure of [Formula: see text] ([Formula: see text]). We report that the lowest energy [Formula: see text] ([Formula: see text]) defects are very strongly bound. These results are consistent, and support the previously reported theoretical and experimental conclusions that [Formula: see text] structures could form.