A structural study employing X-ray diffraction has been made on a two-dimensional (2D) self-organized compound VO(X)(C(12)H(28)N)(y) comprising inorganic vanadium oxides and organic dodecylammonium surfactants. Coexisting periodic phases of a 2D centered rectangular structure and a lamellar structure have thus been identified and closely followed as a function of temperature, elucidating the changes in the distinct structures and their interplay in the system. (C) 2008 Elsevier B.V. All rights reserved.