It's interesting to see fairly complex structures for the first two group 15 elements, and at least, at long last, I have come to be appreciate the beauty of those 3rd period elements silicon, phosphorous and sulfur. My deepest familiarity with the latter two basically derives from biochemistry.
In organic chemistry, on a few rare occasions, I messed around with the higher phosphorous halides, no big deal there.
At one point in my career, I was involved in industrial Vilsmeier type chemistry, at least peripherally, where the counter ion was PF6-. We left that project because of exotherms making it problematic on an industrial scale. This ion shows up fairly frequently in the ionic liquid literature. One part of this battery paper showed it decomposing to give HF; but I didn't end up discussing it, because the paper was too rich for a blog post. That isn't a good thing, and certainly wouldn't be desirable if one were trying to extinguish an industrial scale battery fire.
How the phosphorous fluorine bond in PFN would behave in high temperatures, I couldn't say. The authors of the Nano Energy paper are, of course, recommending it as a flame retardant, so there's that.
There were a lot of other fluorine bonds in this paper. Fluorine bonds in general are proving to be incredible environmental problems, particularly in water and in air.
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