Krypton tetrafluoride

Krypton(IV) fluoride is a hypothetical inorganic chemical compound of krypton and fluorine with the chemical formula KrF4. At one time researchers thought they had synthesized it, but the claim was discredited. The compound is predicted to be difficult to make and unstable if made. Theoretical analysis indicates KrF4 would have an approximately square planar molecular geometry.

Synthesis
The claimed synthesis was by passing electric discharge through krypton-fluorine mixture:


 * Kr + 2F2 -> KrF4

Physical properties
The claimed compound formed white crystalline solid. Thermally, it is less stable than XeF4.