Syntheses and structure determination of the YIII complexes with ethylenediaminetetraacetic acid (H4edta) and trans-1,2-cyclohexanediaminetetraacetic acid (H4cydta) are reported. The crystal and molecular structures of the complexes, as well as their molecular formulas and compositions, were determined by single-crystal X-ray structure analyses, NMR, IR, thermogravimetric measurements, and elementary analyses. The crystal of the Na[YIII(edta)(H2O)3]·5H2O complex belongs to the orthorhombic crystal system and space group Fdd2. The crystal data are as follows: a = 19.355(5) Å, b = 35.431(11) Å, c = 12.122(3) Å, V = 8313(4) Å3, Z = 16, M = 544.23, Dc = 1.739 g·cm−3, µ = 2.908 mm−1 and F(000) = 4480. The final R and Rw are 0.0483 and 0.1172 for 3284 (I > 2σ(I)) unique reflections, R and Rw are 0.0678 and 0.1440 for all 8499 reflections, respectively. The YIIIN2O7 part in the [YIII(edta)(H2O)3]− complex anion has a pseudo-monocapped square antiprismatic nine-coordinate structure, in which the six coordinated atoms (two N and four O) from the edta ligand and three water molecules are coordinated to the central YIII ion directly. The crystal of the Na[YIII(cydta)(H2O)2]·5H2O complex belongs to the triclinic crystal system and \documentclass[12pt]{minimal}
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