The gadolinium complex with triethylenetetraaminehexaacetic acid (abbreviated as H6TTHA), K4[Gd2(HTTHA)2].14H2O was synthesized in aqueous solution, and its crystal structure was determined by X-ray diffraction method. The crystal is monoclinic, space group P21/n, with a=1.1266(5)nm, b=2.5686(4)nm, c=2.2076(8)nm, β=102.50(3)°, V=6.237(6)nm^3, Z=4, Dc=1.812g/cm^3. The complex is a binuclear molecule, each gadolinium ion is coordinated by three nitrogen atoms and four carboxyl oxygen atoms from one TTHA, and two carboxyl oxygen atoms from another TTHA, forming a coordination polyhedron of tricapped trigonal prism.

Key words: CRYSTAL STRUCTURE, GADOLINIUM COMPLEX, TTHA P