Crystals of a new uranyl selenate, [NH3(CH2) 9NH3][(UO2)(SeO4)(SeO 2OH)](NO3) (1), were prepared by isothermal evaporation from aqueous solution at room temperature. The crystal structure was solved by the direct method Pbar 1 , a = 10.7480(7), b = 13.8847(9), c = 14.6363(10) Å, α = 109.9600(10)°, β = 103.212(2)°, γ = 90.4090(10)°, V = 1990.0(2) Å3, Z= 4) and refined to R 1 = 0.0379 (wR 2 = 0.0636) for 8515 reflections with |Fo| ≥ 4σF. The structure is based on [(UO2)(SeO 4)(SeO2OH)]-layers parallel to the (001) plane. In the structure of 1, there are two crystallographically independent 1,9-diammoniononane cations forming micelles in which the hydrocarbon chains are packed crosswise. The micelles are cylinders with an elliptical cross section and a rough surface. They are organized by the principle of hydrophilic and hydrophobic interactions. The cylinders are separated from each other by layers of triangular NO 3 - groups. Compound 1 is an example of organic-inorganic composites with a unidimensional organic substructure in which the protonated chain-like diamine molecules arranged crosswise form cylindrical supramolecular templates. © 2010 Pleiades Publishing, Ltd.