A lamella-structured inorganic-organic zirconium-monododecyl phosphate crystalline hybrid was investigated as an anhydrous proton conductor. Inorganic zirconium ions were coordinated by OH groups of a phosphate moiety from organic monododecyl phosphate. The inorganic-organic zirconium-monododecyl phosphate hybrid showed a lamella structure with crystalline ZrP, and the thermal stability increased up to 230 degrees C. A maximum proton conductivity of 2 x 10(-3) S cm(-1) was obtained at 150 degrees C under anhydrous conditions. The high proton conductivity under high temperature and anhydrous conditions could be explained by considering the interaction between Zr ions and the phosphate group, and the phosphate concentration in the lamella-structured inorganic-organic zirconium-monododecyl phosphate hybrid. (c) 2007 Elsevier B.V All rights reserved.