For succeeding in a structure determination from powder diffraction data, the way is long and difficult before the final step which is the refinement. In fact, here we are interested in the whole route between an unknown material and a known crystal structure and to the pitfails which may prevent from being able to refine something.
Powder diffraction is an ancient technique.
It would be an error to believe that it is obsolete. There is no sign that powder diffraction could disappear, on the contrary. This method is predominantly selected for a first contact with an inorganic solid state compound. The content of this hypertext tutorial follows a definite scenario. We will make the hypothesis that this researcher has just done an original synthesis by any method, or that his job is the characterization of a compound a priori unknown.