Synthesis, and Crystal and Molecular Structure of Heptaaquabis (1-hydroxy-2-naphthoato)lanthanum(III) 1-Hydroxy-2-naphthoate Hydrate and the Isomorphous Neodymium(III) Salt, [M{C10H6(OH)CO2}2(H2O)7][C10H6(OH)CO2]·H2O (M=La, Nd)

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Abstract
The light lanthanoid(III) (La or Nd) 1-hydroxy-2-naphthoate crystals indicated in the title were obtained and their structures were determined by the X-ray diffraction method using their single crystals. They are orthorhombic with the space group P212121, Z=4. The unitcell axis lengths of the lanthanum(III) complex are: a=11.985(4), b=40.21(5), and c=7.017(1) Å. The central metal atom is ennea-coordinated and is in a tricapped trigonal-prism geometry, where two carboxylate ions act as the unidentates, and the other coordinating positions are occupied by water oxygen atoms. The non-coordinated carboxylate ion is hydrogen-bonded to two ligated water oxygen atoms with its respective carboxylato oxygen atoms. The complex molecules are not directly bridged by the carboxylate ions, but the complexes are linked by hydrogenbondings in the a- and c-axis directions. Such hydrophilic and the hydrophobic layers of the naphthalene rings, both of them being parallel to the ac-plane, are laid alternately in the crystal.