Publications by authors named "Ian Swainson"

Boron neutron capture therapy (BNCT) has been extant for decades and continues to be practiced in many centers around the globe. Most of the active clinical trials utilize boronophenylalanine as the drug containing boron atoms. The important aspect that has been added to the BNCT practice is the use of an F-18 radiolabeled analog for ascertaining targeting and monitoring follow-up studies.

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Four new double perovskites, SrLaMReO(6) (M = Mg, Mn, Co, Ni) in which Re(5+) (5d(2)) is present, were prepared via conventional solid state reactions and characterized by X-ray and neutron powder diffraction, XANES, SQUID magnetometry, and muon spin relaxation (μSR). Synchrotron X-ray and neutron diffraction experiments confirmed that all compounds crystallize in the monoclinic P2(1)/n structure type, which consists of alternately corner-shared octahedra of MO(6) and ReO(6). Rietveld refinement results indicated anti-site mixing of less than 7% on the M/Re sites.

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Synchrotron powder diffraction data from methylammonium tin bromide, CH(3)NH(3)SnBr(3), taken as a function of temperature, reveal the existence of a phase between 230 and 188 K crystallizing in Pmc2(1), a = 5.8941 (2), b = 8.3862 (2), c = 8.

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The compound La(3)Re(2)O(10) has been synthesized by solid-state reaction and characterized by powder neutron diffraction, SQUID magnetometry, and heat capacity measurements. Its structure consists of isolated [Re(2)O(10)](9-) dimer units of two edge-shared ReO(6) octahedra, separated by La(3+) within the lattice. The Re-Re distance within the dimer units is 2.

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An examination of the tilt modes and other low-frequency modes is made for an isolated, untilted perovskite layer, which maps very simply to the ABX4 perovskites. A sheet of pure tilts exists at the Brillouin Zone boundary at {xi, (1/2), zeta}. An instability is also found at all wavevectors which can be described as continuously varying from pure tilts to pure layer displacements as a function of the wavevector.

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The transformation of ammonium cyanate into urea, first studied over 170 years ago by Wöhler and Liebig, has an important place in the history of chemistry. To understand the nature of this solid state reaction, knowledge of the crystal structure of ammonium cyanate is a prerequisite. Employing neutron powder diffraction, we demonstrate conclusively that, in the structure of ammonium cyanate, the NH(4)(+) cation forms N-H.

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The decrease in D-->A bond lengths, previously reported for some Lewis acid/base complexes, in going from the gas to the solid phases is investigated by obtaining an accurate crystal structure of solid ND(3)BF(3) by powder neutron diffraction. The B-N internuclear distance is 1.554(3) A, 0.

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The crystal structure of chlorofluoromethane, CH(2)ClF, has been determined at 100 and 30 K using indexing, packing considerations and Rietveld refinement of neutron powder profiles. There is only one phase, in monoclinic space group P2(1) and with two molecules in the unit cell occupying general positions. The structure has close packing in several directions and there are weak hydrogen bonds forming zigzag chains.

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