This communication reports the first intercalation into VOPO4 . 2H(2)O performed through a solid-state reaction at room temperature. Ethyleneurea, EU (2-imidazolidone) was intercalated into the oxovanadium phosphate by grinding in a mortar stoichiometric amounts of both reagents at room temperature for 30 min. C, H and N elemental analyses of the obtained intercalation compound gave the formula VOPO4 . (EU) . H2O. The profile of the absorption bands due to the VOPO4 lattice vibration around 1000 cm(-1) was retained after reaction, providing evidence that an intercalation compound and not merely a salt of V-P-O species was produced. For alpha-VOPO4 . 2H(2)O, the interlayer distance is 0.75 nm, whereas for the EU intercalation compound it is 0.95 min. The obtained SEM micrographs show that the microstructure of VOPO4 . 2H(2)O is changed after reaction, with a total exfoliation of the oxovanadium matrix. (C) 2002 Elsevier Science (USA).1662277278