W. Watson, R. J. Williams, N. Stemple
Feb 1, 1972
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Journal
Journal of Inorganic and Nuclear Chemistry
Abstract
Abstract The crystal structure of tris(acetylacetonato)(1,10-phenanthroline) europium(III), Eu(C 6 H 7 O 2 ) 3 (C 12 H 8 N 2 ), has been determined by single crystal X-ray diffraction techniques. A total of 4697 independent reflections were measured by counter methods and 2855 were considered to have an intensity significantly above background. The complex crystallizes in the monoclinic space group P2 1 c with four molecules per unit cell. The cell dimensions are a 0 = 9·670(8) A , b 0 = 21·339(5) A , c 0 = 16·497(5) A and β = 116° 11(10)′. The observed and calculated densities were found to be 1·37 g/cm −3 . The structure was refined by least-squares methods and a conventional R factor of 0·0334 was obtained for 1123 reflections. The calculated R for all 2855 observed reflections is 0·065. The molecules are monomeric and the europium ion is coordinated to eight ligand atoms which form a distorted square antiprism. Six EuO bond lengths average 2·397 A and two EuN bond lengths average 2·643 A. The distortion of the antiprism reduces the symmetry sufficiently for all characteristic electronic transitions to become allowed, and the full multiplicities are seen in the emission spectrum.