A novel tricyclic azacrown ether 4,13-dioxa-1,7,10,16-tetraaza-1,16: 7,10-bis(ethylene)-9,18-diacetic acid cyclooctadecane-8,17-dione has been prepared. The crystal structure of the compound was determined by X-ray diffraction method. It belongs to monoclinic crystal system, space group P2_1/c with a = 0.87474(17) nm, b = 1.3967(3) nm, c = 0. 94309(19) nm; β = 111.18(3)°; Z = 4, V = 1.0744(4) nm~3, D_c = 1.411 g/cm~3, μ = 0.110 mm~(-1), F(000) = 488, R_1 = 0.0678, wR_2 = 0.1850.

Key words: CROWN ETHER, CARBOXYLIC ACID, CRYSTAL STRUCTURE