scholarly journals Challenges and Solutions for Handling and Characterizing Alkali-Tc-Oxide Salts

MRS Advances ◽  
2018 ◽  
Vol 3 (21) ◽  
pp. 1191-1200
Author(s):  
Jamie L. Weaver ◽  
Chuck Soderquist ◽  
Nancy Washton ◽  
Paul Gassman ◽  
Eric Walter ◽  
...  
Keyword(s):  
Method Development ◽  
Advanced Characterization ◽  
Magic Angle Spinning ◽  
Lessons Learned ◽  
Magic Angle ◽  
Paramagnetic Resonance ◽  
Characterization Methods ◽  
X Ray ◽  
Similar Characterization ◽  
Angle Spinning

ABSTRACTThough not often discussed explicitly in literature, sample handling and preparation for advanced characterization techniques is a significant challenge for radiological materials. In this contribution, a detailed description is given of method development associated with characterization of highly radioactive and, in some cases, hygroscopic oxides of technetium. Details are given on developed protocols, fixtures, and tooling designed for x-ray and neutron diffraction, x-ray absorption, Raman spectroscopy, magic angle spinning nuclear magnetic resonance, and electron paramagnetic resonance. In some cases, multiple iterations of improved sample holder design are described. Lessons learned in handling Tc compounds for these and similar characterization methods are discussed.

A 13C and 15N nuclear magnetic resonance study of solid ammonium thiocyanate

1987 ◽  
Vol 65 (5) ◽  
pp. 941-946 ◽  
Author(s):  
Ross M. Dickson ◽  
Michael S. McKinnon ◽  
James F. Britten ◽  
Roderick E. Wasylishen
Keyword(s):  
Ammonium Thiocyanate ◽  
Nuclear Magnetic Resonance Study ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Chemical Shielding ◽  
X Ray ◽  
Shielding Constants ◽  
Angle Spinning ◽  
Good Agreement ◽  
C Nmr

The static 13C nmr powder pattern for solid ammonium thiocyanate is analyzed to obtain the 13C chemical shielding anisotropy, 321 ± 7 ppm, and the 13C–14N dipolar splitting, 1295 ± 25 Hz. Slow magic angle spinning 15N nmr experiments are analyzed to obtain a nitrogen chemical shielding anisotropy of 415 ± 15 ppm. The 13C–14N dipolar splitting leads to an effective C—N bond length of 1.19 ± 0.01 Å, in good agreement with the value of 1.176 Å reported from accurate X-ray and neutron crystallographic studies. In solid NH4NCS absolute values of the average shielding constants [Formula: see text] and ct[Formula: see text] are 52 and 34 ppm, respectively. Comparison of calculated and observed [Formula: see text] values indicates that intermolecular interactions decrease the 13C and 15N shielding constants by approximately 10 and 30 ppm, respectively.

Structural Properties of a Dimeric Phenylcyanamidocopper(I) Complex, [{Cu(PPh3)2(C6H5NCN)}2]

2000 ◽  
Vol 53 (12) ◽  
pp. 971 ◽  
Author(s):  
Eric W. Ainscough ◽  
Andrew M. Brodie ◽  
Peter C. Healy ◽  
Joyce M. Waters
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Structural Properties ◽  
Structure Determination ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Cross Polarization ◽  
X Ray ◽  
Angle Spinning

The X-ray crystal structure determination of bis[-(phenylcyanamido)bis(triphenylphosphine)copper(I)], [{Cu(PPh3)2(C6H5NCN)}2], (1) is reported. The complex has a centrosymmetric dimeric structure with the phenylcyanamide ligands bridging the copper atoms in a -1,3-fashion. The structure is compared with that of the 4-methylphenylcyanamido complex, [{Cu(PPh3)2(4-MeC6H4NCN)}2] (2), and the differences observed in the Cu–P bond lengths compared with changes in the solid state 31P cross-polarization magic-angle spinning (CPMAS) spectra of the two complexes.

X-ray diffraction and solid-state 119Sn CP-MAS NMR studies of some triaryltin(IV) chlorides

2003 ◽  
Vol 81 (11) ◽  
pp. 1187-1195 ◽  
Author(s):  
Jordan M Geller ◽  
Ian S Butler ◽  
Denis FR Gilson ◽  
Frederick G Morin ◽  
Ivor Wharf ◽  
...  
Keyword(s):  
Solid State ◽  
Chemical Shift ◽  
Magic Angle Spinning ◽  
Mas Nmr ◽  
Spin Coupling ◽  
Magic Angle ◽  
X Ray ◽  
Tin Chloride ◽  
Angle Spinning ◽  
Spin Spin Coupling

The solid-state 119Sn cross-polarization (CP) magic angle spinning (MAS) NMR spectra of a series of triaryltin chlorides of the form Ar3SnCl have been acquired. The indirect spin-spin coupling constants (J(119Sn-35Cl)), quadrupolar-dipolar shifts (d(119Sn-35Cl)), and the 119Sn chemical shift tensors were extracted. For the spectrum of triphenyltin chloride (I) the validity of the first-order perturbation approximation was tested by comparing results of both the perturbation and cubic-equation approaches and a variable-temperature NMR study undertaken to investigate the influence of the previously reported molecular motion in the solid. The X-ray crystal structures of the tris(o-tolyl)tin chloride (II) and tris(p-tolyl)tin chloride (IV) complexes have been examined. They belong to the monoclinic and triclinic space groups P21/n and P[Formula: see text], respectively, which are different from the previously reported tris(m-tolyl)tin chloride (III) complex, which crystallizes in the space group R3 and has threefold molecular symmetry. The structures and NMR properties of the complexes with meta-substituents are quite different from those with ortho- or para-substituents having axially symmetric shift tensors with small spans and larger J values.Key words: aryltin chlorides, magic angle spinning NMR, tin-chlorine spin-spin coupling, 119Sn chemical shift tensor, crystal structure.

scholarly journals Structure of nanocrystalline calcium silicate hydrates: insights from X-ray diffraction, synchrotron X-ray absorption and nuclear magnetic resonance

2016 ◽  
Vol 49 (3) ◽  
pp. 771-783 ◽  
Author(s):  
Sylvain Grangeon ◽  
Francis Claret ◽  
Cédric Roosz ◽  
Tsutomu Sato ◽  
Stéphane Gaboreau ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Calcium Silicate ◽  
Electron Probe ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Calcium Silicate Hydrates ◽  
Angle Spinning ◽  
X Ray Absorption

The structure of nanocrystalline calcium silicate hydrates (C–S–H) having Ca/Si ratios ranging between 0.57 ± 0.05 and 1.47 ± 0.04 was studied using an electron probe micro-analyser, powder X-ray diffraction,29Si magic angle spinning NMR, and Fourier-transform infrared and synchrotron X-ray absorption spectroscopies. All samples can be described as nanocrystalline and defective tobermorite. At low Ca/Si ratio, the Si chains are defect free and the SiQ3andQ2environments account, respectively, for up to 40.2 ± 1.5% and 55.6 ± 3.0% of the total Si, with part of theQ3Si being attributable to remnants of the synthesis reactant. As the Ca/Si ratio increases up to 0.87 ± 0.02, the SiQ3environment decreases down to 0 and is preferentially replaced by theQ2environment, which reaches 87.9 ± 2.0%. At higher ratios,Q2decreases down to 32.0 ± 7.6% for Ca/Si = 1.38 ± 0.03 and is replaced by theQ1environment, which peaks at 68.1 ± 3.8%. The combination of X-ray diffraction and NMR allowed capturing the depolymerization of Si chains as well as a two-step variation in the layer-to-layer distance. This latter first increases from ∼11.3 Å (for samples having a Ca/Si ratio <∼0.6) up to 12.25 Å at Ca/Si = 0.87 ± 0.02, probably as a result of a weaker layer-to-layer connectivity, and then decreases down to 11 Å when the Ca/Si ratio reaches 1.38 ± 0.03. The decrease in layer-to-layer distance results from the incorporation of interlayer Ca that may form a Ca(OH)2-like structure, nanocrystalline and intermixed with C–S–H layers, at high Ca/Si ratios.

Synthesis, X-ray diffraction and solid-state 31P magic angle spinning NMR study of ?-tricalcium orthophosphate

1996 ◽  
Vol 7 (7) ◽  
pp. 457-463 ◽  
Author(s):  
M. Bohner ◽  
J. LeMa�tre ◽  
A. P. LeGrand ◽  
J.-B. D'Espinose de la Caillerie ◽  
P. Belgrand
Keyword(s):  
Solid State ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nmr Study ◽  
Angle Spinning
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