It was first discovered by Cady that when fluorine is bubbled through 3 N nitric acid, then a remarkable compound, fluorine nitrate ($\ce{FNO3}$) is formed. It boils at -42℃ and is a very strong oxidizing agent and is capable of liberating iodine from iodides and in gaseous states, it explodes around 200-300℃.

**Reference**

 1. Don M. Yost and Alan Beerbower THE REACTION OF FLUORINE WITH NITRIC ACID AND WITH SOLID POTASSIUM NITRATE TO FORM NO3F. *J. Am. Chem. Soc.* April **1935**, 57(4) 782. https://doi.org/10.1021/ja01307a520

 2. Prof. Dr. Otto Ruff, Dr. Walter Kwasnikie,  Die Fluorierung der Salpetersäure. Das Nitroxyfluorid – NO3F, April **1935** https://doi.org/10.1002/ange.19350481604 [German paper]