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Electron diffraction patterns of the fullerene C(60) in the gaseous state have been obtained by volatilizing it from a newly designed oven-nozzle at 730 degrees C. The many peaks of the experimental radial distribution curve calculated from the scattered intensity are completely consistent with icosahedral symmetry for the free molecule. On the basis of this symmetry assumption, least-squares refinement of a model incorporating all possible interatomic distances led to the values r(g)(C(1)-C(2)) = 1.458(6) angstroms (A) for the thermal average bond length within the five-member ring (that is, for the bond fusing five- and six-member rings) and r(g)(C(1)-C(6)) = 1.401(10) A for that connecting five-member rings (the bond fusing six-member rings). The weighted average of the two bond lengths and the difference between them are the values 1.439(2) A and 0.057(6) A, respectively. The diameter of the icosahedral sphere is 7.113(10) A. The uncertainties in parentheses are estimated 2sigma values.

Increasing evidence indicates widespread occurrence of pharmaceuticals and personal care products (PPCPs) in municipal effluent discharges and surface waters. Studies that characterize the fate and effects of PPCPs in aquatic systems are limited, and to our knowledge, data regarding pharmaceutical accumulation in fish of effluent-dominated ecosystems have not been previously reported. In the present study, fish populations were sampled from a reference stream and an effluent-dominated stream in north Texas, USA. Lepomis macrochirus, Ictalurus punctatus, Cyprinus carpio, and Pomoxis nigromaculatus were killed; the liver, brain, and lateral filet tissues dissected; and the tissues stored at -80 degrees C until analysis. Fish tissues were extracted using solid-phase extraction and then analyzed by gas chromatography-mass spectrometry in the negative chemical ionization mode. The selective serotonin reuptake inhibitors (SSRIs) fluoxetine and sertraline and the SSRI metabolites norfluoxetine and desmethylsertraline were detected at levels greater than 0.1 ng/g in all tissues examined from fish residing in a municipal effluent-dominated stream. To our knowledge, the present study is the first report of SSRI residues in fish residing within municipal effluent-dominated systems.

The rotational dynamics of C(60) in the solid state have been investigated with carbon-13 nuclear magnetic resonance ((13)C NMR). The relaxation rate due to chemical shift anisotropy (1/9T1(CSA)(1)) was precisely measured from the magnetic field dependence of T(1), allowing the molecular reorientational correlation time, tau, to be determined. At 283 kelvin, tau = 9.1 picoseconds; with the assumption of diffusional reorientation this implies a rotational diffusion constant D = 1.8 x 10(10) per second. This reorientation time is only three times as long as the calculated tau for free rotation and is shorter than the value measured for C(60) in solution (15.5 picoseconds). Below 260 kelvin a second phase with a much longer reorientation time was observed, consistent with recent reports of an orientational phase transition in solid C(60). In both phases tau showed Arrhenius behavior, with apparent activation energies of 1.4 and 4.2 kilocalories per mole for the high-temperature (rotator) and low-temperature (ratchet) phases, respectively. The results parallel those found for adamantane.