The Purpose of This Lab Was to Observe the Gyromagnetic Ratio of The19f Signal in HBF4

Isaac Sarver

NMR II

The purpose of this lab was to observe the gyromagnetic ratio of the19F signal in HBF4 and the 1H in glycerin, to observe the 19F in Teflon and simultaneously observe 1H and 19F in fluororic acid.

We used last week's set up to measure all of the signals. The simple observation of 19F in Teflon peaked at 3375.68 Gs, with a half width, half maximum height of .56 Gs when hit with a frequency of 13,581 kHz. The simple measurement of 19F in HBF4 produced a peak at 3269.92 Gs and a HWHM of .60 Gs when hit with a frequency of 14 MHz. 1H in HBF4 produced a peak at 3476.32 Gs and HWHM of .6 Gs at the same frequency.

The follow table is a tabulation of the data and the calculations for the gyromagnetic ratios of 19F in HBF4 and 1H in glycerin. I did the standard deviation in parallel instead of in series because of the HWHM is a reading of standard deviation in B0. I then used the resulting standard deviation of each reading of gyromagnetic ratios to find a weighted average.

Fluororic acid (HBF4)
B (Gs) / Off B (Gs) / B0 (Gs) / Off HWHM (Gs) / HWHM (Gs) / F0 (kHz) / γ (kHz/Gs) / Δγ (kHz/Gs)
3186.88 / -3.68 / 3183.20 / -3.16 / .52 / 13581.0 / 26.8070 / .00437912
3186.88 / 1.08 / 3187.96 / .56 / .52 / 13601.0 / 26.8064 / .00437248
3186.88 / -1.24 / 3185.64 / -1.72 / .48 / 13691.0 / 27.0034 / .00406877
3229.88 / -1.00 / 3228.88 / -.48 / .52 / 13771.0 / 26.7974 / .00431564
3254.88 / -.54 / 3254.34 / .00 / .54 / 13871.0 / 26.7809 / .00444381
3276.88 / .28 / 3277.16 / -.20 / .48 / 13971.0 / 26.7861 / .00392332
3300.88 / -4.16 / 3296.72 / -3.64 / .52 / 14071.0 / 26.8178 / .00423004
3323.88 / -.56 / 3323.32 / -.08 / .48 / 14171.0 / 26.7922 / .00386970
3154.88 / -.28 / 3154.60 / .24 / .52 / 13471.0 / 26.8309 / .00442277
3133.88 / -2.08 / 3131.80 / -1.64 / .44 / 13371.0 / 26.8256 / .00376885
Ave / 26.8256
St Dev / .00131494
Glycerin (C3H5(OH)3)
B (Gs) / Off B (Gs) / B0 (Gs) / Off HWHM (Gs) / HWHM (Gs) / F0 (kHz) / γ (kHz/Gs) / Δγ (kHz/Gs)
3277.82 / -.30 / 3277.52 / -.10 / .20 / 14000 / 26.8388 / .00163775
3300.12 / -.04 / 3299.08 / .08 / .12 / 14100 / 26.8538 / .000976775
3253.82 / .16 / 3257.98 / .08 / .08 / 13900 / 26.8069 / .000658245
3208.82 / .04 / 3230.86 / .12 / .08 / 13800 / 26.8374 / .000664527
3208.02 / -.08 / 3207.94 / -.16 / .08 / 13700 / 26.8333 / .000669172
Ave / 26.8299
St Dev / .00034851

19F in fluororic acid has a gyromagnetic ratio of 268.256 MHz/T with a standard deviation of 13.1494 kHz/T. 1H in glycerin has a gyromagnetic ratio of 268.299 MHz/T with a stand deviation of 3.4851 kHz/T. Both of these are too high and out of range of the experimental values provided by nmrwiki.org. 19F comes in at 251.7 MHz/T and 1H comes in at 267.51 MHz/T.