th  - 1988 - 51st ENC Conference

i m 3 I
31p SOLID STATE NMR STUDIES OF ZrP, Mg3P2, MgP4, AND CdPS3,
R. A. Nissan* and'T. A. Vanderah, Chemistry Division, Research Department,
Naval Weapons Center, China Lake, CA 93555.
The 31p solid state NMR spectra of ZrP, Mg3P2, MgP4, and CdPS3 are reported. Static and marc
angle spinning (MAS) spectra were obtained for each compound. In all cases, chemical shift anisotropy and
the effects of dipolar broadening were sufficiently reduced by the MAS method to reveal the isotropic
hemical shifts for each crystallographically distinct phosphorus. The observed resonances were assigned to
he different types of phosphorus by considering the structural details of each compound. In ZrP the two
.'hemical shifts of +128.4 and +187.5 ppm (relative to 85% H3PO4) were assigned to P occupying the
¢¢yckoff 2d and 2a sites, respectively. Assignments were confirmed by quenching of ZrP0.92 thus
mriching the 2a site. In Mg3P2, two resonances from the 24d and 8a site P atoms were observed at -262.3
md -239.6 ppm, respectively. In MgP4 two types of phosphorus, one type coordinated to two Mg and two
P and the other to three P and one Mg, gave chemical shifts of-109.2 and -6.1 ppm, respectively. From
,?.dPS3 only one resonance at +104.9 ppm is observed as all P atoms are crystallographically:equivalent.
I HIGH RESOLUTION SPECTRA OF LIQUIDS IN INHOMOGENEOUS ENVIRONMENTS
AS OBTAINED BY MASS
V. Rutar, Department of Chemistry, Iowa State University, Ames, Iowa 50011
Magic angle sample spinning successfully reduces line broadening arising from
differences in magnetic susceptibility. Although this advantage seems
superficial in NMR spectroscopy of solids, it offers interesting new
possibilities in studies of some "liquid-like" samples. Many biological systems
represnet significant examples where MASS improves resolution and sensitivity.
IH and 13C spectra of plant seeds facilitate nondestructive determination of oil
composition thus allowing rapid development of better varieties. Detection of
dissolved sugars monitors germination processes without destroying the sample.
MASS of liquids can be applied also to other objects which are small enough to
fit into the spinner cavity (typical volume is about 1 cm~), because spinning
frequencies are moderate (100-500 Hz). Precise balancing of rotors is not
essential and mechanical stress does not appear dangerous.
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