The

1. For each non-equivalent atom A its Voronoi-Dirichlet polyhedron (VDP, Fig. 1) is constructed, and only the atoms X that are

2. For all contacts A-X

3. For each atom type two kinds of radii are determined: Slater's radius, r

4. For each pair A-X the reference distance D(A-X) is determined, which is equal to the minimum of two sums: R

5. The D(A-X) values are modified to take into account the features of the structure. For this purpose, if A is a metal atom or both A and X are non-metals, all distances

6. If A is a metal and with the D(A-X) values obtained at the previous steps it does not form any valence bond, the corresponding D(A-X) value is increased up to the maximal distance value of the closest group of contacts. As a result the closest contacts A-X will be considered as valence (the metal atom cannot have zero coordination number).

7. If both A and X are metals and at least one of them is

8. If A is a metal and X is a boron atom connected to O or F atoms then the bond A-X (if any) is broken (D(A-X) = 0).

9. If there are several non-equivalent pairs (A, X) and, hence, several D

10. All contacts A-X with

Thus, in contrast to standard crystallochemical approach, when the bonds A-X

The

The

With these three algorithms the user can compute adjacency matrices in an automated mode, which is very important for the analysis of large amounts of crystal structures.