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The reaction of Eu metal with HOPr(i)/toluene solutions yielded the mixed Eu(2+)/Eu(3+) alkoxide [Eu(4)(OPr(i))(10)(HOPr(i))(3)] x 2HOPr(i) (1), in contrast to the other lanthanide metals, which exclusively yield trivalent lanthanide ions in the alkoxides formed. Metathesis between EuCl(3) and 3KOPr(i) and stoichiometric hydrolysis yielded the square-pyramidal Eu(5)O(OPr(i))(13) (2), and metathesis with EuCl(3) and 3KAl(OPr(i))(4) gave EuAl(3)(OPr(i))(12) (3). The structures of these compounds were determined by single-crystal X-ray diffraction. IR spectroscopic studies showed that the solid-state molecular structure of the three alkoxides remained close to intact in solution. Further characterizations were made with UV-vis spectroscopy, differential scanning calorimetry, and solubility studies. It was also found that 1 can be converted to 2 by oxidation with dioxygen, but 2 was not reduced by Eu metal to 1. The reactions of 2 and 1 with Al(4)(OPr(i))(12) in toluene/HOPr(i) solvent were studied by IR and UV-vis spectroscopy; 2 reacted completely to form 3 in 2 h at 75 degrees C, while 1 reacted to yield 3 and other unidentified Eu(2+) containing product(s) in the same time.

The method of the joint probability distribution functions has been applied to the case in which observed (with errors) and calculated structure factors are available, the latter referred to a part of the structure with finite errors in the coordinates, the thermal parameters and the scattering factors. Results obtained by other authors are confirmed and generalized. A new relationship is found to estimate the parameter sigmaA, affecting the reliability of the estimates of cos(varphi-varphip). Some practical applications are described.

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