Trace Determination and Pressure Estimation of Fluorine F₂ Caused by Irradiation Damage in Minerals and Synthetic Fluorides

Abstract

Irradiated alkali and earth alkali halides can form metal colloids and halogen molecules, which stay trapped inside the crystal. In this paper we provide F NMR spectroscopic evidence of trapped F fluids in heavy ion-bombarded synthesized LiF crystals as well as in a variety of the mineral Villiaumite (NaF). This is the 2nd mineral in which F is unambiguously detected in nature. The trace quantification of the latter is in the order of magnitude of 10 mol g . Pressures and densities of the F fluids are estimated based on the theory of nuclear spin relaxation in dilute gases.

Perfluoro Alkyl Hypofluorites and Peroxides Revisited

“…The longitudinal relaxation time T 1 of the dissolved F 2 was determined by an inversion recovery experiment to be T 1 =13.5 ms (Figure S1.13 in the Supporting Information). This is approximately 300 times larger than T 1 for gaseous fluorine of 0.045 ms in the pressure range from 1 to 2 bar . This indicates that the fast relaxation owing to the spin‐rotation mechanism observed for gaseous fluorine is hindered and proves that the fluorine is indeed dissolved in peroxide 2 b .…”

“…This is approximately 300 times larger than T 1 for gaseous fluorine of 0.045 ms in the pressure range from 1t o2bar. [47] This indicates that the fast relaxation owing to the spin-rotation mechanism observed for gaseous fluorine is hindered and proves that the fluorine is indeed dissolved in peroxide 2b.…”

Fluoride in Human Health and Nutrition

“…The goal is to monitor the intake of fluoride and maintain it at adequate levels so that optimal protection against dental caries is achieved, without excessive intake Štepec and Ponikvar-Svet: Fluoride in Human Health and Nutrition resulting in the appearance of adverse effects. Basic requirements for accurate and precise determination of fluorine in any type of the sample are: (1) the sample has to be appropriately pre-treated so that the required form can be determined; (2) interfering reactions or ions have to be effectively suppressed; (3) the final concentration of fluorine must be above the detection limit of the method; and (4) the result should be reported together with a measurement uncertainty (MU) evaluated in accordance Guide to the Expression of Uncertainty in Measurement (GUM).117. 117…”

“…Finally, it is worth mentioning that in addition to these databases many studies reported the contents of total and/or free fluoride in different food items. [221][222][223][224][225][226][227] The results of these studies are difficult to compare, because the determined level of fluorine in food is among other influenced by: (1) the locality in which the food is grown; (2) the differences in the amount of fertilizer and pesticides applied or differences in feeding routine; (3) the type of processing the food receives; (4) the amount of water and the fluoride content of water used in their preparation; (5) different sample pre-treatment procedures; and (6) the differences in the analytical procedures. In addition, the re-…”

“…the only EU directive related to fluorine in diet addresses the maximum content of F in animal feed. [295][296][297] More research and actions regarding: (1) the content of F in different food items; (2) reporting the results in accordance to the GUM; (3) the intakes of fluoride and its possible adverse effects in relation to interaction with other food components should be encouraged to provide support for further development and implementation of legislation concerning fluorine.…”