https://doi.org/10.1351/goldbook.C01060
An atom holding a set of ligands in a spatial arrangement which is not superposable on its mirror image. A chirality centre is thus a generalized extension of the concept of the asymmetric carbon atom to central atoms of any element, for example $\ce{N^{+}abcd}$, $\ce{Pabc}$ as well as $\ce{Cabcd}$ .