3F2 + Cl2 => ClF3
Gas at room temperature.
Corrosive - burns skin. Fatal if inhaled. Causes serious permanent eye and skin damage. Strong oxidiser - ignites or reacts violently with organic or inorganic combustible substances, including every known fuel as well as human tissue with no ignition delay. It can corrode any substance containing oxygen. Decomposes in water to form a variety of hazardous compounds including Hydrofluoric Acid, which melts metals, semimetals and glass and destroys inner body tissues, leaving outer tissues untouched, rendering symptoms invisible. Hydrofluoric Acid in particular damages the heart, liver, kidneys and nerves.
Reacts with Phosphorus to form Phosphorus Trichloride, which is lethal in just a few minutes in concentrations of 600ppm or higher.
Reacts with Sulphur to form Sulphur Dichloride, which reacts with water to form Hydrogen Chloride, which is corrosive when it reacts with body tissue, causing inflammation of the nose throat and upper respiratory tract and pulmonary edema when inhaled. In contact with the skin, it causes severe burns and causes serious permanent eye damage. Also reacts with Sulphur to form Sulphur Tetrafluoride, that reacts with water to form Hydrofluoric Acid (as Chlorine Trifluoride does) and Thionyl Fluoride, which is irritant to the eyes, skin and respiratory system.
Also known as N-stoff, Nazi rocket fuel and chemical weapon developed exclusively by the SS.
In other words, chlorine trifluoride corrodes, melts or ignites any substance, depending on how much oxygen it contains.
Make chlorine trifluoride by mixing chlorine and fluorine.