The purely inorganic microporous compound [H(3)O][Fe(4)F(4)(AsO(4))(3)] x 3 H(2)O (1), which contains novel cubane-like Fe(4)F(4) cages, exhibiting a 3D configuration with channels of dimensions 8 A x 8 A running along the [001], [010], and [100] directions, presents antiferromagnetic interactions.