Chlorine trifluoride
From Wikipedia, the free encyclopedia
| Chlorine trifluoride | |
|---|---|
  |
|
| Molecular formula | ClF3 |
| Molar mass | 92.45 g/mol |
| CAS number | [7790-91-2] |
| UN number | 1749 |
| Density | 4.1 kg/m3 (gas) |
| Solubility (water) | Hydrolysis |
| Melting point | -76.3°C |
| Boiling point | 11.75°C |
| Geometry | Trigonal bipyramidal T-shaped |
| Bond angle | 120° |
| Thermodynamic data | |
| Standard enthalpy of formation ΔfH°gas |
-158.87 kJ/mol |
| Standard molar entropy S°gas |
281.59 J.K–1.mol–1 |
| Heat capacity Cp | 60.40 J.K–1.mol–1 |
| Disclaimer and references | |
Chlorine trifluoride is a colourless, very poisonous gas that condenses to a pale-yellow liquid. It was first prepared in 1912 by the electrolysis of molten NaCl/HF, but is now generally made by reacting fluorine gas with 3% aqueous sodium hypochlorite solution:
4F2 + 2NaOCl → 2ClF3 + 2NaF + O2
When pure it is stable to 180° in glass vessels, but above this temperature it decomposes by a free radical mechanism to the elements.
ClF3 is a very strong oxidizing and fluorination agent. Several metals give chlorides and fluorides, phosphorus yields PCl3 plus PF5, sulfur SCl2 plus SF4. H2S explodes on being mixed with ClF3 at room temperature.
Contents |
[edit] Military applications
Under the code name N-stoff ("substance N"), chlorine trifluoride was investigated for military applications by the Kaiser Wilhelm Institute in Nazi Germany from slightly before the start of World War II. Tests were made against mock-ups of the Maginot Line fortifications and it was found to be an effective combined incendiary weapon and poison gas. From 1938 construction commenced on a partly bunkered, partly subterranean 3,176 hectare munitions factory at Falkenhagen which was intended to produce 50 tonnes of N-stoff per month, plus Sarin. However by the time it was captured by the advancing Red Army in 1944, only about 30 to 50 tonnes had been made, at a cost of over 100 German Reichsmark per kilograma. N-stoff was never actually used in war. [1]
[edit] Rocket propellant
Chlorine trifluoride has been investigated as a high-performance storable oxidizer in rocket propellant systems. However, handling concerns prevented it from being used. Clark summarized the difficulties, "It is, of course, extremely toxic, but that's the least of the problem. It is hypergolic with every known fuel, and so rapidly hypergolic that no ignition delay has ever been measured. It is also hypergolic with such things as cloth, wood, and test engineers, not to mention asbestos, sand, and water — with which it reacts explosively."[2]
[edit] See also
[edit] External links
- National Pollutant Inventory - Fluoride and compounds fact sheet
- NIST Standard Reference Database
- WebElements
[edit] References
- ^ "Bunker Tours" report on Falkenhagen
- ^ Clark, John D. (2001). Ignition!. UMI Books on Demand. ISBN 0-8135-0725-1.
- Groehler, Olaf (1989). Der lautlose Tod. Einsatz und Entwicklung deutscher Giftgase von 1914 bis 1945. Reinbek bei Hamburg: Rowohlt. ISBN 3-499-18738-8.
- Ebbinghaus, Angelika (1999). Krieg und Wirtschaft : Studien zur deutschen Wirtschaftsgeschichte 1939 - 1945. Berlin: Metropol, 171-194. ISBN 3-932482-11-5.
Note a: Using data from Economic History Services and The Inflation Calculator, we can calculate that 100 Reichsmark in 1941 is approximately equivalent to $540 US dollars in 2006. Reichsmark exchange rate values from 1942 to 1944 are fragmentary.
