We describe a procedure to extract a single determinant wave function from x-ray charge density structure factors. The orbitals obtained can be seen as Hartree-Fock orbitals constrained to give the experimental density to a prescribed accuracy. The method is applied to beryllium metal. From our wave function we extract the binding energy and work function for the crystal. Both are in qualitative agreement with independent experiments. There is no evidence for non-nuclear maxima in the charge density.