ISSN:
1572-8862
Keywords:
Polyoxometalate
;
preyssler
;
europium
;
uranium
;
phosphotungstates
;
tungstophosphates
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Abstract The crystal structures of (Nh4)11.5K0.5[ Eu(OH2)P5W30O110] ·24 H2O, K5H5 [Eu(OH2)P5W30O110] ·31 H2O, and (NH4)11[U(OH2)P5Wn30O110 ·12 H2O have been determined. In each case, the anion has the overall virtual C5v symmetry previously observed for the sodium derivative, [NaP5W30 110]14- The encrypted Eu3+ and U4+cations lie on the C5 axis, but are displaced further than the Na+ from the equatorial plane defined by the five phosphorus atoms. Only minor differences are observed between the structures of the two salts of the europium derivative, although solutions of these display31P NMR spectra with chemical shifts differing by 10 ppm, provisionally attributed to the effects of protonation of the anion, The most significant feature of the three new structures is the presence of a water molecule within the central cavity and coor-dinated to the Eu3+ or U4+ cation.The coordination spheres of the central cations can therefore be described as monocapped pentagonal antiprisms.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01165802
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