Thirteen new ternary coordination compounds of lanthanides with 1,10-phenanthroline-N-oxide (PhenNO) and acetylacetone (Hacac), Ln(PhenNO)(acac)3 (Ln = La, Pr, Nd, Sm-Lu) were prepared and characterized by elemental anal., IR spectra, UV spectra, fluorescence spectra, molar conductance, TG and DSC. The result of the single crystal x-ray structure anal. for Sm(PhenNO)(acac)3 shows that metal ion is 8-coordinated, being bonded to 6 acac O atoms and the O atom and N atom from the PhenNO, in the form of a distorted dodecahedron. Crystals are monoclinic, P21/n, with a 12.241(2), b 12.333(3), c 18.751(2) ? b 104.85(3)? Z = 4, and R = 0.083.

Key words: CRYSTAL STRUCTURE DETERMINATION, INFRARED SPECTROPHOTOMETRY, TERNARY COMPLEX, YTTERBIUM COMPLEX, PRASEODYMIUM COMPLEX, LANTHANUM COMPLEX, NEODYMIUM COMPLEX, PHENANTHROLINE P, THULIUM COMPLEX, LUTETIUM COMPLEX