A novel 3D EDTA-linked (EDTA＝ethylenediamine-N,N,N',N'-tetraacetate) heterometallic antimony-praseodymium complex [Sb₂-μ₄-(EDTA)₂Pr(H₂O)₅]NO₃•4H₂O has been synthesized and characterized by elemental analysis, FT-IR spectrum, TG-DSC and X-ray diffraction analyses. It crystallizes in the orthorhombic system, space group Pnn2 with a＝1.07031(2) nm, b＝2.30805(4) nm, c＝0.72343(2) nm, V＝1.78711(7) nm³, Z＝2, D_c＝2.202 g/cm³, F(000)＝1164, μ＝2.955 mm^－1, GOF＝1.000, the final R₁＝0.0203 and wR₂＝0.0545 [I＞2σ(I)]. In the title complex, the Pr(III) ion is nine-coordinated. The coordination polyhedron around each praseodymium atom is a distorted tricapped trigonal prism with four oxygen atoms from four carboxylic groups and five oxygen atoms from five H₂O molecules. The Sb(III) ion is coordinated by two N atoms and four O atoms from an EDTA, together with a lone electron pair in the equatorial position. It shows the possible pyrolysis reactions of experimental and calculated percentage mass losses in the thermal decomposition process.

Key words: antimony(III), praseodymium(III), complex, crystal structure, aminopolycarboxylic acid