Ab initio methods were used to calculate structural and reactivity features of C(6)H(4)X(-) ions for X=F, Cl, Br, and I. Recent techniques were used to adapt basis sets along with pseudopotentials for the X atoms. Two possible stable structures are suggested for these molecules : the anion C(6)H(4)X(-) and the complex X(-)...C6H4. The calculations showed that F-...o-benzyne complex is stable when F- coordinates to the ortho hydrogen of o-benzyne. The other halides showed a different behavior when compared with F-...C6H4. These complexes have the halide coordinated between the protons (in ortho and meta) of the benzyne ring. The diffuse character of the electronic cloud changed the order of stability of some halides. The I-...C6H4 complex was calculated to be more stable than the anion form, unlike the behavior observed for the ether complexes.