Like the atomic structure it represents, the net is 3-dimensional and periodic. It contains all the information on the connectivity of the vertices, i.e. which pairs of vertices, called neighbours, are linked by an edge. Thus, it provides a convenient mathematical abstraction to classify crystal structures. However, it is important to note that this representation is dependent on the choice of vertices and therefore a crystal may be represented by different nets . Moreover, reconstructing the full crystal from the net necessitates additional data, such as the unit cell parameters and the nature and exact geometric placement of the vertices and the edges .