Deuteron Magnetic Resonance Study of Several Deuterated Ammonium Salts

Deuteron magnetic resonance spectra were observed in ND₄Cl, ND₄Br, ND₄ClO₄, ND₄BF₄, ND₄IO₃, and (ND₄)₂SO₄ in their powder form. Absorption patterns characteristic of the rapid reorientation of ND₄⁺ ions were obtained. For the first four compounds, the absorption line consists of a sharp single line; for the remaining two it has structure which is due to small quadrupole coupling. For (ND₄)₂SO₄, the angular dependence of the resonance pattern was measured with a single crystal specimen. The following values of the quadrupole coupling constant and asymmetry parameter were obtained: $$\begin{array}{ccc}{\mathrm{ND}}_4{\mathrm{IO}}_3:& \text{\hspace{0.17em}\hspace{0.17em}|eqQ|/h=3.9±0.3\hspace{0.17em}}\mathrm{kc},& \text{η=1.0−0.8,}\\ ({\mathrm{ND}}_4{)}_2{\mathrm{SO}}_4:& \text{\hspace{0.17em}\hspace{0.17em}|eqQ|/h=4.17±0.05\hspace{0.17em}}\mathrm{kc},& \text{η=1.0−0.95,}\end{array}$$ and $$\text{|eqQ|/h=2.00±0.05\hspace{0.17em}}\mathrm{kc}\text{,\hspace{0.17em}\hspace{0.17em}η=1.0−0.8.}$$ The results of the experiment were discussed in relation to the crystal structure, crystalline field effect, and the deformation of ND₄⁺ ion in the crystal. It was concluded that the observed quadrupole coupling for ammonium sulfate is mainly due to a direct effect of the distortion of the ammonium ion in the crystal rather than to the crystalline field effect. The observed asymmetry parameter for ammonium iodate did not agree with the reported crystal structure.