Basic Separation Theory:

The isotopes along with that we are concerned are those of uranium; namely U²³⁵ and U²³⁸.  In sequence that the isotopes of uranium might be separated through the gaseous diffusion process, it is essential in which the uranium is in a gaseous state.  That is accomplished by combining the uranium with fluorine to form uranium hexafluoride that is a gas at workable temperatures and pressures. The other advantageous quality of uranium hexafluoride is which fluorine has no isotopes to additional complicate the separation procedure.  In common, the following discussion is concerned along with the separation of U²³⁵F₆ and U²³⁸F₆.