Pentafluoroselenium hypofluorite

Pentafluoroselenium hypofluorite is a selenium compound with the chemical formula SeOF6. It was discovered at 1959.

Preparation
Pentafluoroselenium hypofluorite can be produced from the reaction of selenium dioxide or selenium oxychloride with fluorine gas in the presence of silver difluoride catalyst. However, the reaction yield is low (14% ), and it is hard to purify due to large amount of SeF6 byproduct.

Pentafluoroselenium hypofluorite can also formed from selenium oxyfluoride and fluorine gas in the presence of potassium fluoride.
 * SeOF2 + KF → K+[SeOF3]&minus; —F2→ K+[SeOF5]&minus; —F2→ KF + SeOF6

The reaction of fluorine gas and Hg(OSeF5)2 produces SeOF6 in much higher yield and with less SeF6.

Reactions
Pentafluoroselenium hypofluorite is reactive, but not as reactive as pentafluorosulfur hypofluorite. It reacts with water to release oxygen gas. It reacts with potassium hydroxide too, forming potassium selenate, potassium fluoride, water and oxygen gas. ：
 * 2 SeOF6 + 16 KOH → 2 K2SeO4 + 12 KF + 8 H2O + O2↑

SeOF6 can also oxidize potassium iodide into iodine. It explodes upon reacting with ethylene, and the reaction with perfluorocyclopentene produces F5SeOC5F9. SeOF6 reacts with sulfur tetrafluoride to produce thionyl fluoride, thionyl tetrafluoride, sulfuryl fluoride, selenium hexafluoride and F5SOSeF5. SeOF6 reacts very slowly with carbon monoxide, and produces F5SeOCFO at 65°C. SeOF6 reacts with bromine to form BrOSeF5.