From memory, that book went in at least four different directions with fluorine compounds. Parts are about increasing specific impulse; parts are about increasing density impulse (fluorine's very dense); parts are about formulating oxidizers hypergolic with kerosene or with hydrogen; parts are about formulating oxidizers for deep space probes, with a melting/boiling point range matched to that thermal environment.
O3F2 is the one that if you add it to liquid oxygen, it makes hydrogen/oxygen combustion hypergolic.
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