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Structural Systematics of Rare Earth Complexes. II. Structural Characterization of Lanthanoid(III) Picrate Hydrates: the Triclinic P1, 11.5 Hydrates of the Later Rare Earths and Yttrium

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1994

Year

Abstract

Picrates of dysprosium(III), holmium(III), erbium(III), thulium(III), ytterbium(III), lutetium(III) and yttrium(III) have been found to crystallize as needles from aqueous solution, seemingly best described as 11.5 hydrates. Single-crystal X-ray structure determinations have been performed at c. 295 K on the Dy , Er , Lu and Y species, and show them to be isomorphous , triclinic, Pi , a 20.043(7) ? 20.019(5), b 11.533(2) ? 11.471(2), c 8.1567(7) ? 8.1538(8) ?, a 88.60(1) ? 88.40(1), ß 87.12(2) ? 87.06(1), ? 75.07(2) ? 75.05(2)°, V 1819 ? 1807 ?3 ( Dy ? Lu; the Y and Er values are intermediate). Complex ions [ Ln ( pic )(OH2)7]2+ are observed, with a pair of uncoordinated picrate anions and 4.5 lattice water molecules; this result is in contrast to that of the monoclinic, P 21/c, series found for La ? Pr and Nd ? Tb, in which the complex cation contains two picrate anions.