Measurement and caiculation of the superexchange interaction through the two-halide bridge in the eclipsed layered compounds (NH3(CHq) Magnetic susceptibility measurements on the eclipsed layered structure series of [NH3(CH2) "NH3)CuX (n =2, 3, 4, and 5 for X =C14 and n =2 for X =C12Br2) indicate that the interplanar superexchange interaction along the linear Cu-Cl-Cl-Cu path has a significantly stronger Cu-Cu distance dependence than that for the typical M-X-M (M =Cu, Mn, Ni, Co; X =F, Cl) path, and a stronger power-law metal-metal distance dependence than previously expected for the two-halide bridge case. Furthermore, the evidence indicates a 10th-power dependence on the halide-halide separation, which appears to be the critical parameter for determining the strength of the two-halide superexchange. Previously unpublished data on the partially bromated compound is included. The results of a Rayleigh-Schrodinger perturbation calculation of the two-halide superexchange strength are presented and the calculated results are compared with experimental values.