For estimating a property of use, for example the activity of a catalyst or the ability to hold a ratio-element in a solid mineral matrix, or a material M.sub.AB whose active element is AB, there are used a descriptor D.sub.AB of the chemical bond between A and B, which has the dimension of an energy, and index R.sub.AB that measures the property of use of said material. The invention also relates to a process for determining the chemical affinity of an element or a set of elements B for a matrix A with a descripor D.sub.AB. The process according to the invention advantageously can be used for the design of new materials whose use produces the formation or the modification of at least one chemical bond or makes it necessary to prevent the formation of said bond.