Unusual Dodecahedral Coordination in the Structure of Ammonium Tetrakis[4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione]praseodymate(III) Monohydrate, NH4Pr(C8H4F3O2S)4.H2O

Roger Lalancette, Michael Cefola, W. C. Hamilton, S. J. La Placa

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The crystal and molecular structure of ammonium tetrakis[4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione]praseodymate(III) monohydrate, NH4Pr(C8H4F3O2S)4· H2O1, has been determined from 2969 observed three-dimensional X-ray film data. The material crystallizes in space group Ci1-P1 of the triclinic system, with two molecules per unit cell. The cell dimensions are: a = 10.10 (2), b = 17.90 (3), c = 12.14 (2) A; α = 78.57(10), β = 103.97 (10), and γ = 86.95 (10)°. (pobsd = 1.65 g cm-3; pcalcd = 1.67 g cm-3.) The molecules are monomeric with the metal dodecahedrally coordinated by the oxygens of the four bidentate ligands (Pr-O, 2.42-2.49 (2) A). The essentially coplanar ligands all show dihedral folding of 10-24° about the 0-0 line in the six-membered chelate ring. In contrast to other structures displaying similar bidentate coordination, each ligand bridges adjacent vertices between the two orthogonal trapezoids in the dodecahedron. The intramolecular sulfur-oxygen distances are 2.8-2.9 A, 0.4 A shorter than the sum of the van der Waals radii, indicating some interaction between these atoms. The structure was refined by the least-squares method to a conventional crystallographic R factor of 11.1%. Molar susceptibilities, measured from 68 to 297°K, obey Curie's law and yield a moment of 3.59 BM.

Original languageEnglish (US)
Pages (from-to)2127-2134
Number of pages8
JournalInorganic Chemistry
Issue number12
Publication statusPublished - Dec 1 1967
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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