X-ray spectroscopy, analyzing crystals for

We report in this paragraph the results obtained by X-ray spectroscopy for the stable oxides, ThOj, UOj, and Pu02- All three compounds crystallize in the CaFj-type structure. We have analyzed their Mjy y and Mm absorption spectra and Mjy y emission spectra of Th02 and UO2. 

The monochromator for x-ray fluorescence spectroscopy is called the analyzing crystal. It differs from all the monochromators described earlier for all the other optical analytical instruments. The effect used in this type of monochromator is not diffraction, but interference. The wavelength of the analyzing light is changed by rotation of the analyzing crystal by certain angle. 

X-ray spectroscopy rivals visible spectroscopy as a tool for elemental analysis. Because the energies of x-rays are much higher than those of visible radiation, however, x-rays usually cause transitions of inner-shell electrons rather than of valence-shell electrons. There are many advantages of this method in spectrochemical analysis. A quantitative analysis of a mixture of rare-earth oxides may be performed or a crystal structure may be determined. A specimen that contains two elements widely separated in atomic number may be studied, or the thickness of a very thin layer of tin plating may be measured. The most widespread use of x-rays has been in the field of metallurgy, but x-rays may also be used to analyze metals, minerals, liquids, glasses, ceramics, or plastics. 

In solution, multinuclear NMR spectroscopy is by far the most informative technique for analyzing the structure and bonding of phosphinocar-benes. In fact, prior to the synthesis and single crystal X-ray analysis of the (phosphino)(phosphonio)carbene 2d,28 the only spectroscopic evidence for the formation of carbenes came from NMR. 

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