Packing patterns in lanthanide–edta complexes: crystal and molecular structures of sodium triaqua(ethylenediaminetetraacetato)dysprosate(III) pentahydrate and caesium diaqua(ethylenediaminetetraacetato)ytterbate(III) trihydrate

Anomalous scattering by praseodymium, samarium and gadolinium and structures of their ethylenediaminetetraacetate (edta) salts

“…We repeated the determination for Sm using X-rays so that the synchrotron experiments could be analyzed with atomic form factors identical (apart from anomalousscattering terms) with those used in the structure determination. Nassimbeni, Wright, van Niekerk & McCallum (1979) reported the structure of the Dy salt in this space group with parameters similar to those found for these other salts. We have adopted their scheme of atomic identification and choice of asymmetric unit to simplify comparison.…”

“…The principal differences among these isomorphous crystals are the result of the different sizes of the lanthanoid ions. The neighbor distances of these ions are listed in Table 3 with corresponding values reported by Nassimbeni et al (1979) for the Dy compound. Corresponding distances for our three structures trend downward consistently with increasing atomic number, with an average decrease of 0.061/k from Pr to Gd; the ionic radii calculated from oxide and chloride structures (Templeton & Dauben, 1954) decrease 0.075/k in the same interval.…”

Sodium (Ethylenediaminetetraacetato)gallate(III) Trihydrate

“…Our previous X-ray absorption fine structure study of a series of lanthanoid(III) ethylenediaminetetraacetato (edta) complexes in aqueous solution has shown that the total coordination number switches from nine to eight at Dy m, where the number of additionally coordinated water molecules changes from three to two (Nakamura et al, 1993;Choppin, 1993). A similar change in the coordination number for the lanthanoid(III)-edta complexes also takes place in the solid state, but at a different ion, Yb HI (Nassimbeni, Wright, van Niekerk & McCallum, 1979).…”

Neutron diffraction study at 37 K of sodium triaqua(ethylenediaminetetraacetato)samarate(III) pentahydrate, Na[Sm(C10H12N2O8)(H2O)3].5H2O

“…The authors reported the structures of KLa/1.8H 2 0 and NaTM.8H 2 0 by X-ray diffraction. A further X-ray determination of the isomorphous NaDy4.8H 2 0 has been reported by Nassimbeni, Wright, van Niekerk & McCallum (1979). H atoms were not located in this X-ray work.…”

“…The X-ray crystal structures of three isomorphous nine-coordinate lanthanide edta complexes have been reported previously: KLa^t.8H 2 0 , NaTb;4.8H 2 0 (Lee, 1967) and NaDyA8H 2 0* (Nassimbeni, Wright, van Niekerk & McCallum, 1979; NWVM hereafter). The structure of a ten-coordinate acid complex, HL£l4.7H 2 0, is given by Lind, .…”