# Non stoichiometry

Hello, I'd like to understand better the relation between non-stoichiometry and partial occupancies. Let's suppose for example that after an Xray analysys I find that in a material a site can be occupied by an atom of type 1 or an atom of type 2 with 50 % probability. Does it usually mean that the material is non stoichiometric and that it is possible to produce a material with different stechiometric ratios or there is no relation?