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Research has been conducted on fluoride ion affinity values for antimony and arsenic pentafluorides. The authors discuss their approach to investigation of these values carried out via utilization of estimated lattice potential energies, and they report that their approach includes the estimation of experimentally based fluoride ion affinity values of SbF (sub)5 and AsF (sub)5.

Research has been conducted on tetramethylphosphonium fluoride. The authors have investigated this compound in solid state, in solutions and in gas phase, and they report that vibrational spectra of the single-crystal structure and the solid possess ionic tetramethylphosphonium fluoride.

Research has been conducted on nickel(II)/uranium(IV) fluorides. The preparation of these fluorides in aqueous media under mild hydrothermal conditions is described.

Research has been conducted on triisopropylsilyl propynal. The authors report that boron trifluoride-catalyzed Rothemund condensation of this compound with 3,4-diethylpyrrole in dichloromethane produce chromophores with special spectroscopic characteristics.

The discovery of unusually well-crystallized samples of gearksutite allowed determination of its crystal structure. The crystals belong to space group P[bar] 1, a = 4.940(1), b = 6.810(1), c = 6.978(1) [Angstrom]; [Alpha] = 101.12(1), [Beta] = 94.86(1), [Gamma] = 110.07(1) [degrees]; V = 213.43(6) [[Angstrom].sup.3]; Z = 2. The structure consists of layers of eightfold-coordinated calcium polyhedra connected through pairs of [[Al.sub.2][F.sub.8][(OH).sub.2]] octahedra which are oriented identically, similar to those observed in other hydroxyl aluminum fluorides. A comparison with other minerals of similar composition is made. The structure data allowed us to reliably index the powder pattern and to show that the reflection intensities are strongly affected by preferred orientation.