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Sand Won’t Save You This Time

In a comment to my post on putting out fires last week, one commenter mentioned the utility of the good old sand bucket, and wondered if there was anything that would go on to set the sand on fire. Thanks to a note from reader Robert L., I can report that there is indeed such a reagent: chlorine trifluoride.
I have not encountered this fine substance myself, but reading up on its properties immediately gives it a spot on my “no way, no how” list. Let’s put it this way: during World War II, the Germans were very interested in using it in self-igniting flamethrowers, but found it too nasty to work with. It is apparently about the most vigorous fluorinating agent known, and is much more difficult to handle than fluorine gas. That’s one of those statements you don’t get to hear very often, and it should be enough to make any sensible chemist turn around smartly and head down the hall in the other direction.
The compound also a stronger oxidizing agent than oxygen itself, which also puts it into rare territory. That means that it can potentially go on to “burn” things that you would normally consider already burnt to hell and gone, and a practical consequence of that is that it’ll start roaring reactions with things like bricks and asbestos tile. It’s been used in the semiconductor industry to clean oxides off of surfaces, at which activity it no doubt excels.
There’s a report from the early 1950s (in this PDF) of a one-ton spill of the stuff. It burned its way through a foot of concrete floor and chewed up another meter of sand and gravel beneath, completing a day that I’m sure no one involved ever forgot. That process, I should add, would necessarily have been accompanied by copious amounts of horribly toxic and corrosive by-products: it’s bad enough when your reagent ignites wet sand, but the clouds of hot hydrofluoric acid are your special door prize if you’re foolhardy enough to hang around and watch the fireworks.
I’ll let the late John Clark describe the stuff, since he had first-hand experience in attempts to use it as rocket fuel. From his out-of-print classic Ignition! we have:
”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. It can be kept in some of the ordinary structural metals-steel, copper, aluminium, etc.-because of the formation of a thin film of insoluble metal fluoride which protects the bulk of the metal, just as the invisible coat of oxide on aluminium keeps it from burning up in the atmosphere. If, however, this coat is melted or scrubbed off, and has no chance to reform, the operator is confronted with the problem of coping with a metal-fluorine fire. For dealing with this situation, I have always recommended a good pair of running shoes.”
Sound advice, indeed. I’ll be lacing mine up if anyone tries to bring the stuff into my lab.

84 comments on “Sand Won’t Save You This Time”

  1. Fred says:

    Everyone should have a “no way, no how” list.

  2. Thomas McEntee says:

    According to the Kirk-Other Encyclopedia of Chemical Technology, 4th Ed, during WWII, Germany ran a 5-ton per day pilot plant to produce ClF3. Chlorine trifluoride oxide (ClF3O) is another extremely powerful oxidative fluorinator. The initial report on its synthesis was published in 1970; this report describes the UV-initiated reaction chlorine trifluoride with oxygen and fluorine. Another is chlorine trifluoride dioxide (ClF3O2, first synthesized in 1972. A key paper to read regarding oxidative fluorinators–including the xenon fluorides and krypton difluoride–is the study “A Quantitiative Scale for the Oxidizing Strength of Oxidative Fluorinators”, Karl O. Christie and David A. Dixon, JACS, 114, 2978-85 (1992)

  3. Feiser N. Feiser says:

    Ah, the old sand bucket. Was out in the hall outside the undergraduate labs. Might have been there since benzene was linear. Top was decorated with cigarette butts, dried gum, bits of paper. Then one day down the hall the THF still is being cleaned out – long over due. Thick clumps of whatever ketyl becomes. Inside, a bright shiny prize of sodium metal that disagrees with the optimistic and impatient grad student’s use of straight ethanol as cleaning aid. Fire erupts. Extinguished by CO2. Humid day, icy glass, beads of water form and follow gravity down. Into and onto sodium metal. Fire erupts. Extinguished by CO2. Repeat several times until it dawns that CO2 will eventually run out. Send terrified lab mate down the hall to fetch savior: sand bucket! Weight of bucket: about 200 lbs. Skinny grad student risks hernia rushing it back to lab, arrives exhausted, collapses in victory like Pheidippides. Firefighting grad student drops damned CO2 tank, plunges bare hand into sand bucket. Screams in pain – sand has been accreted by age into protoconcrete, impermeable to human flesh, spatulae, metal rulers, etc. Fire meanwhile burns itself out. Sand bucket replaced for next sucker.

  4. jose says:

    “I am become death, the (liquid) destroyer of worlds.”

  5. Mark says:

    That made my morning! What a fine combination of chemistry, history, and comedy.
    I get the soundtrack to an old Stooges short in my head when reading that…

  6. Wavefunction says:

    “Ignition” totally rocks! What a rambunctious journey through liquid rocket fuel propellants. Too bad it’s out of print.

  7. Brooks Moses says:

    It does sound like a book that I’d really like to read. It would be nice if Dover would find a slot for it in their reprint catalog!

  8. BACE says:

    On a different note, what do you think of this:
    People will die from paying the cost, not of the disease.

  9. In the back stacks says:

    get yer ignition here

  10. milkshake says:

    I was in lab where they analysed oxygen isotopic content in silicates and other minerals.
    They had a big tank of BrF3 there. It made an impression on me – you take dry sand and gas it with brominefluoride and off goes O2
    Oh, and the apparatus was a benchtop, the tank parked right next to it. it had an exhaust but no fume hood in sight 🙂

  11. Fred says:

    Interesting that this should show up on a day we are discussing difficult fires: Ethanol fires from rail and tanker accidents are more difficult to extinguish than gasoline fires. Ethanol dissolves the foam commonly used to fight fires.

  12. Anonymous BMS Researcher says:

    When my father was in high school some fellow students started a thermite reaction in the chem lab. It burned its way through several floors and finally went quite a ways into the concrete floor of the basement (from my father’s descriptions I’m visualizing the scene in Alien when the creature’s blood burns through the decks of the spacecraft). Fortunately, no people happened to be directly in its path…

  13. tom bartlett says:

    “When my father was in high school some fellow students started a thermite reaction in the chem lab. It burned its way through several floors and finally went quite a ways into the concrete floor of the basement”
    Must have been a pretty big quantity.
    Anyway, ClF3 sounds way cool. Xenon Fluorides are also good candidates for the “no way, No how” list.

  14. milkshake says:

    XeF2 is actually a nicely behaved heavy salt-like solid, not very reactive. You can but it from Aldrich but it is dear.

  15. TNC says:

    Baran actually used XeF2 in a recent synthesis.

  16. Thomas McEntee says:

    Milkshake: As of January 2005, XeF2 also was offered for sale on the English-language web site of Russia’s Kurchatov Institute and recommended for uses in the surface treatment and improving wear-resistance for styrene-butadiene rubbers, acrylonitile-based rubbers, EPDM and isoprene-based rubbers.
    An interesting synthesis of XeF2 suitable for students was described by JH Holloway in 1966 (J Chem Ed) in which a sealed Pyrex bulb containing fluorine and xenon is placed in sunlight. After a period, tiny crystals of XeF2 are observed to form.

  17. A-nony-muse says:

    What, no one chose to comment on the burning RAW CHICKEN FLESH pics in the Air Products MSDS for ClF3??? That’s not something you see every day!

  18. Derek Lowe says:

    I’ve used XeF2 myself – a rather penetrating smell, which I sampled despite trying not to. It’s the higher xenon fluorides, I believe, that are a bit rambunctious. I’ll probably add them to the list, too, and do a post on ’em. . .

  19. MedChemSF says:

    A-nony-muse: I was more impressed with the flaming nitrile glove.
    I can imagine chicken on fire, but I don’t think I’ve ever thought about what it would take for a chemical to set my gloves off.

  20. Kevin says:

    I hate to admit it but I’ve worked with both. I’ve even seen someone redesign a TGA to handle these gases. Funny, thro the HS2 worried me more.
    Catalyst design can be messy at times.

  21. Mike says:

    Careful. You are going to give the Truthers another idea about how the government brought down the WTC towers, WTC 7, and what really caused the Tunguska blast.

  22. Jim says:

    Reminds me of a Captain Marvel comic book story from (probably) the late 1940s where Captain Marvel was fighting some evil genius who had created a universal solvent. This chlorine trifluoride sure sounds almost as scary.

  23. MB says:

    The Nazis also experimented with loading chlorine trifluoride into artillery shells to use against the Maginot fortifications. One of those babies slamming into your pillbox could ruin your whole day.

  24. Huycbald says:

    I just love it that there are people in the world who can answer the question, “Will anything set sand on fire?” And, in the affirmative, no less.
    Great stuff!

  25. I have a beloved copy of “Ignition!” right here. Did y’all know that Dr. Clark was a well-known member of the Baker Street Irregulars? He wrote the famous essay “Watson was a Woman,” offering proof that Dr. Watson was really Irene Adler. A truly amazing man. The introduction to “Ignition!” was written by Isaac Asimov. By the way, in the chapter where he discusses chlorine triflouride, Clarke mentions that someone nanaged to synthesize enough chlorine pentaflouride (!) to characterize…

  26. Robert says:

    I just found your site, and I have to say that these “Things I Won’t Work With” segments are both hilarious and informative. I’m a cheist myself, though most of my work has been quality control with analytical instruments, so I’m not familiar with all the reagents and processes being mentioned. But I’m certainly learning interesting new things by looking them up. (Not to mention leanring what to stay the hell away from!) Anyway, I hope you keep up with these. you’ve certainly earned a bookmark from me!

  27. This brings back memories of sitting on an airliner talking to a sales engineer for a chemical company. He was completely unaware of what happens when you combine fluorine gas and water. Yikes!

  28. Bob Holness says:

    So in this case we need a metal filing bucket?

  29. SFOtter says:

    Years back, when I worked as a machinist, we occasionally had to mill blocks of magnesium for semi-conductor mfgs.
    Some apprentice decided he could cut faster than the programmer had set and ratcheted up the speed & feed rate.
    The resulting fire destroyed a $40k Matsuraa mill and part of the floor.

  30. Irritant says:

    I believe this is what Chuck Norris has for breakfast when he has a sore throat.

  31. Spooge says:

    The first reagent in the Krol Blade.

  32. Chunkstyle says:

    As I recall, ClF3 was simply dropped on London by those same Nazis, who built the 5 ton/day plant for it. Pretty nasty, when the compound itself is the bomb…

  33. Seriously says:

    I’ve worked with ClF3 before, had excellent results with maintaining LP-CVD process chamber and no accidents when handled properly. Get careless and you can get burned. Handle with respect, and the benefits are miraculous.

  34. Rissa says:

    “Suitable extinguishing media: None.”
    Says it all really.

  35. Yanes says:

    We use bromine triflouride in the the oilfield, nasty similar oxidizer. Pretty potent mental image: burning snow.

  36. Eric says:

    How, pray tell, did they figure out that ClF3 is toxic? I mean, besides the whole catching-fire-to-raw-flesh-or-water thing.

  37. Ilya says:

    So this is the stuff that aliens (from the film) had for blood…

  38. How on earth do you synthesize that stuff?! Not that I’d want to try…

  39. milkshake says:

    obviously they had to find some material that does not get eaten by it. I suppose they used some metal alloy that coats itself with a protective layer of fluoride. The starting material, fluorine gas is bad enough – on contact it speedily burns through the skin like a flame…
    By the way Teflon was invented in WWII as the only material that can withstand uranium hexafluoride in the gas diffusion enrichment plant.

  40. anonymous says:

    #36 Eric- I’ll give you three guesses, and the first two don’t count.

  41. Ariel says:

    @milkshake: No it wasn’t. That’s simply not true about teflon. First uranium hexafluoride is not that reactive, second teflon was invented by 3M much later than that.

  42. Anonymous says:

    RE #39 and #41
    US Patent No. US 2,230,654
    Title Tetrafluoroethylene polymers
    Publication date February 4, 1941
    Inventor Roy J. Plunkett
    Applicant KINETIC CHEMICALS INC Wilmington, DE

  43. milkshake says:

    UF6 is nasty to most organics. From what I heard they had a major problem with finding the right material for the seals. Also to keep the moving parts from seizing (such as inside the valves) the conventional petroleum-based lubricants could not be used. Eventually they developed perfluoro polymer compositions specifically for the Oak Ridge plant.

  44. Luke says:

    Apparently ClF3 has many industrial uses in reactions which would normally require elemental fluorine, simply because it’s easier to liquefy and handle as a liquid than fluorine – and I suppose it’s not any scarier than bulk liquid fluorine.
    It’s an interesting material, but I agree, I don’t know that I’d work with it.

  45. Rick says:

    Hello Derek,
    What a fantastic posting. I’m sending it to all my friends in the hazardous response community! I ran a fluorine facility for 5 years, and was really glad to move onto my next assignment. Keep up the good work. May I post a link to you on my blog?

  46. Gavin says:

    #39 #41 and #42
    PTFE was discovered accidentally in 1938 by a young scientist looking for something else. Roy Plunkett was a chemist for E.I. du Pont de Nemours and Company (Du Pont). He had earned a PhD from Ohio State University in 1936, and in 1938 when he stumbled upon Teflon, he was still only 27 years old. Plunkett’s area was refrigerants. Many chemicals that were used as refrigerants before the 1930s were dangerously explosive. Du Pont and General Motors had developed a new type of non-flammable refrigerant, a form of Freon called refrigerant 114. Refrigerant 114 was tied up in an exclusive arrangement with General Motor’s Frigidaire division, and at the time could not be marketed to other manufacturers. Plunkett endeavored to come up with a different form of refrigerant 114 that would get around Frigidaire’s patent control. The technical name for refrigerant 114 was tetrafluorodichloroethane. Plunkett hoped to make a similar refrigerant by reacting hydrochloric acid with a compound called tetrafluoroethylene, or TFE. TFE itself was a little known substance, and Plunkett decided his first task was to make a large amount of this gas. The chemist thought he might as well make a hundred pounds of the gas, to be sure to have enough for all his chemical tests, and for toxicological tests as well. He stored the gas in metal cans with a valve release, much like the cans used commercially today for pressurized sprays like hair spray. Plunkett kept the cans on dry ice, to cool and liquefy the TFE gas. His refrigerant experiment required Plunkett and his assistant to release the TFE gas from the cans into a heated chamber. On the morning of April 6, 1938, Plunkett found he could not get the gas out of the can. To Plunkett and his assistant’s mystification, the gas had transformed overnight into a white, flaky powder. The TFE had polymerized.

  47. AO says:

    Contrary to being the nigh on uncontainable monster suggested by your amusing blog entry this MSDS suggests dry powder and CO2 are suitable extinguishing media.
    In the event of eye contact, it also suggests washing with water?!

  48. sdancer says:

    In the event of eye contact, it’s almost always water, since whatever entered the eye is pretty sure to have reacted with water, salt, fat, and proteins already in the worst possible way (in the case of ClF3, that sounds like a lot of “worst”) and needs to be washed out. The rinsing procedure is based on the same concept as the production of homeopathic medicine: dilute until it’s gone. That is also reflected by the suggested rinsing for at least 15 minutes. I guess further treatment would involve calcium to get rid of the HFl.
    I find the measure noted for ingestion quite nice, however…

  49. JWC says:

    It may interest you to know, Mr. Lowe, that not only this particular article but your entire “Things I won’t work with” list has made the cut for my own personal Internet Archive.
    Now to get my hands on that book…

  50. In the event of eye contact, it’s almost always water, since whatever entered the eye is pretty sure to have reacted with water, salt, fat, and proteins already in the worst possible way (in the case of ClF3, that sounds like a lot of “worst”) and needs to be washed out. The rinsing procedure is based on the same concept as the production of homeopathic medicine: dilute until it’s gone. That is also reflected by the suggested rinsing for at least 15 minutes. I guess further treatment would involve calcium to get rid of the HFl.
    I find the measure noted for ingestion quite nice, however…

  51. Anon says:

    ****ing hell, one more thing to keep normal folk such as myself restricted access to.

  52. ST says:

    I’ve worked with both UF6 and ClF3(among other things equally dangerous). UF6 does not scare me one bit. Reactive?…maybe over time, but not near what ClF3 can do. When I worked with ClF3 we processed(neutralized) over 18,000 lbs of the stuff out of ton cylinders in about 2 months using 3000 gallon reactors. We ran a few experiments(off the books) with it and I about wet my trelleborg level B suit just from dropping one drop of the stuff into a 5 gallon bucket of water. Sounded the equivalent of an M-80 firecracker with just a drop. Not to mention that the stuff is a calcium seeker which will dissolve your bones from the inside out with the only thing in your arsenal to stop it being a tube of calcium gluconate…and that’s just a distraction for it. Very very interesting stuff.

  53. MZ says:

    Working at the Minkwitz group in the late 80s / early 90s a lot of us, the Diploma and PhD students, were working with strong Fluorine or Oxygen based oxidizers or Lewis acids/bases. Water-free liquid HF was very often the only solvent that reasonably worked and inert atmospheres, very high integrity reactors and low temperatures were mandatory to control most reactions.
    ClF3 is a given nasty component and earned deservedly its reputation, but other things like ClF and KrF2 are not too friendly either – all of us had to become experts in material science for vessels, reactors, high-integrity connections and valves / valves seats in addition to become conclude our studies as unharmed inorganic chemists.
    In this forum, ST has made very valuable comments about the bulk/commodity use of such oxidizers – I value and appreciate them very much, good stuff.
    As part of the “Fluorine for the Atomic Age” program of the glorious 1950s and 1960s, Air Products and Allied Chemical had 18-wheel road tankers with 30.000L tank capacities to transport liquified Fluorine and Chlorine Trifluoride on American highways around the country to the various application sites (a friend of mine has a 16-page color brochure of that!). Imagine a road collision with another gasoline-loaded 18-wheeler… 😉
    Any Uranium enrichment plant, e.g. former Allied Signal (Chemical), Honeywell, Areva/Comurhex, etc. are using massive quantities of the above chemicals for direct fluorination of UF4 and/or reactor, diffusion membrane or centrifuge in-situ clean.
    In Asia – spec. Japan, large quantities (virtually hundreds) of 20kg ClF3 cabinets are installed in Semiconductor fabs for in-situ between-run cleans of Silicon or Tungsten CVD or VPE tools. They train people to handle the stuff, keep users alert and install the necessary safety equipment.
    For further application reference of Fluorine-based chemistry, please search for the publications (“(Ten years of) Inorganic Halogen Oxidizer Research” – 1.400 pages) of Karl Otto Christe, a retired professor at USC in LA. He is what I call the best reference you can have in respectful handling of a huge number of extremely reactive components. Or, in other words “The Fluorine God” if you want to call him so – which he would be the first to decline that title, as he is such an understatement person.
    There are too many to mention or honor in this research (Ruff, Schmeisser, Haas, Appelman, the Wilsons, Olah, Kornath, Naumann, Klapoetke, oooff…), but I tried to add my little piece to this puzzle – so just search the Internet for more if you wish…
    Oh, nearly forgot – if you feel the urgent desire to go and try making and handling ClF3 yourself – just go to the G. Brauer’s HANDBOOK OF PREPARATIVE INORGANIC CHEMISTRY, 1st Ed. 1961, p. 155. Just watch your back in the lab – and even more, your front…
    …and don’t forget what Calvin said to Hobbes: “Technological Progress goes Boink…” :-))
    Just keep it a “Boink” and try to avoid the “Bang” (lab) or “Boooom” (industry)…

  54. bio merhem says:

    In the event of eye contact, it’s almost always water, since whatever entered the eye is pretty sure to have reacted with water, salt, fat, and proteins already in the worst possible way (in the case of ClF3, that sounds like a lot of “worst”) and needs to be washed out. The rinsing procedure is based on the same concept as the production of homeopathic medicine: dilute until it’s gone. That is also reflected by the suggested rinsing for at least 15 minutes. I guess further treatment would involve calcium to get rid of the HFl.
    I find the measure noted for ingestion quite nice, however…

  55. Cave Johnson says:

    We’re done here.

  56. abadidea says:

    Comment #56: The internet’s done here. You won.

  57. Health Cover says:

    Ignition! is such a good read, I remember reading it when I was still in the university and I totally enjoyed it. It is full of interesting stuff and it made me want to try out different things and be more adventurous in life.

  58. fbartho says:

    Unfortunately, the safetygram PDF (from the article) with the store of the fire, appears to be broken.
    Anyone have an updated link to that story?

  59. David Marjanović says:

    The link is indeed broken. The file “cannot be found” and may have been “deleted, renamed, or” be “temporarily unavailable”.

  60. Colin says:

    Thanks for the article.
    Ignition! also mentions that a stream of liquid ClF3 dissolves Teflon like sugar in hot water. I’d call this the most alarming compound ever, but they also made ClF5 and a mixture of what they called Hydrazoid P, which would burn quietly and then explode if it was spilled.

  61. joeylawn says:

    LOVED the comment on #3:
    “Might have been there since benzene was linear.”

  62. Oldnuke says:

    Burning chicken? Now I know what to use if the chicken population in Southern Delaware gets out of control!
    Brings a new meaning to the word “Roasters”…

  63. Quuxum says:

    Yes! My library (UPitt) has a copy of “Ignition!” *requests*

  64. RoCkEt says:

    Product Details
    Ignition! An Informal History of Liquid Rocket Propellants by John D. Clark (1972)
    £1,222.20 used (1 offer)
    Sounds like a book you should
    ‘forget to take back…..’

  65. Would anyone who has been a aspect of your program from the beginning mind sending me copies on the prior letters? I am signed up now but unfortunately did not hear of the until now. Many, many thanks in advance.

  66. Chris Jenkins says:

    From the pubchem registry @ NIH:
    “Incompatibilities: acids; ammonium fluoride; carbon tetrachloride; fluorinated polymers; fuels, hydrogen-containing materials; iodine; metals, or metal oxides, or metal salts or non-metals, or non-metal oxides; nitrocompounds; organic material; polychlorotrifluoroethylene; refractory material; water.”
    Can anyone think of a substance NOT covered by this list that is even *remotely* common?

  67. Kelly St. Clair says:

    #68: They should just cross all of that out and replace it with “baryonic matter.”

  68. Ralph says:

    #69: Just baryonic matter? I bet given a positronium sample, ClF3 would take a crack at stealing the electrons and leaving the positrons sobbing in the gutter with a black eye.

  69. Andrew says:

    a friend of mine told me a story of an old industrial site (now long closed) that used this oh so pleasant chemical, the father of this friend was tasked with refilling the tank of this hellish chemical, when about halfway through he noticed the pressure gauge on the pressurised container still read 0, meaning it was broken, he went to his supervisor who told him to hell with it finish filling it, he said no and went to the next person up who also said hell no and they changed the gauge,
    the tank was at 1.5X its normal ‘full’ pressure,

  70. Sailorleo says:

    #68: My best guess at the most common materiel not on the list would be something on the order of… charmonium, maybe?

  71. Galane says:

    If scrith (Larry Niven’s “Ringworld” series) was real, this stuff might possibly not react with it.

  72. Kenny Strawn says:

    I wonder if compounds like ClF4N3 and/or ClF3(N3)2 have ever been synthesized…

  73. Kenny says:

    I wonder if compounds like ClF4N3 and/or ClF3(N3)2 have ever been synthesized…

  74. Archon1995 says:

    Galane: If scrith can be punctured by suitably-large applications of kinetic energy, then it’d react. Though probably not as quickly as non-synthetic materials.

  75. John Cowan says:

    Oh, it can be. An asteroid slammed into the Ringworld and punched a hole in the scrith, in the process raising an Olympus Mons-class mountain. Not surprisingly, the native name for the mountain translates as Fist-Of-God.
    But when you’re dealing with something whose interatomic bonding has to approximate the strong force just to keep the Ringworld from disintegrating (I mean, an object the size of the Earth’s orbit that revolves once every 30 days?!), mere-shmere chemistry just won’t have much effect.

  76. 3 prep,” hid as being a “critical ѕystem update,” but Apple doesn’t issue these kinds of updates, so users ijstalled it manually-a telltale sign of malware. It is a biit more lke a case of distinguishing between your mother and herr clone. For Windows, PPTP and L2TP can also be an option, most users wiull go with Open – VPN oor SSTP because of the better security features.

  77. John Savard says:

    In trying to figure out how the atoms in ClF3 are bound together, it seems like it is simply a ClF molecule and an F2 molecule bound together as one, sharing their covalent bonds; not something with a really unstable bond like hydrogen peroxide or FOOF.
    But that should mean that ClF3 isn’t any worse than plain old fluorine gas (even slightly milder due to being 1/4 chlorine) – except, of course, that the higher molecular weight means it’s a liquid, and hence much denser and much more concentrated. Of course, maybe that’s “bad enough”, accounting for all the dangerous properties noted here, since fluorine is pretty nasty stuff itself.
    But then, I’m not a chemist, and I may have missed some important facts.

  78. Randolph Finder says:

    From Wikipedia
    ClF3 is approximately T-shaped, with one short bond (1.598 Ã…) and two long bonds (1.698 Ã…).[10] This structure agrees with the prediction of VSEPR theory, which predicts lone pairs of electrons as occupying two equatorial positions of a hypothetic trigonal bipyramid.
    And some of the additional nastiness is that ClF3 is a liquid just below room temperature so once you put it under a little pressure, it is liquified at room temperature and thus will stay around as a liquid (dissolving various things and also boiling to go after things slightly farther away.)

  79. Aigarius says:

    Sooooo, not the best stuff for a Super Molotov Cocktail?

  80. Getheren says:

    Bob Holness …

    A metal filing bucket would be a gloriously bad idea. The person trying to use it would be an excellent candidate for a Darwin Award. The fluorines for sure, and maybe some of the chlorines, would be all over those metal atoms like dumb on Dubya. You’d have that metal-fluorine fire that Mr. Clarke recommends a good pair of running shoes for.

    To put a fire out, you have to (1) reduce the energy input, (2) deprive it of fuel, and/or (3) deprive it of oxidiser. These are the three legs of the Fire Triangle. Alas, when you have ClF3 involved, those three legs become essentially unbreakable. It comes to the party with its own energy input; its fuel is, for all practical purposes, damn near any form of baryonic matter; and it is the oxidiser that all other oxidisers bow humbly before.

    Huge quantities of dry ice might cool things down so that the CTF has a little less, er, fire in its belly, but eventually that dry ice will be gone, and the chilled CTF will unchill and get back to business.

    Got a CTF fire? The best strategy is pretty much to contain it and let it burn itself out on its own without even trying to put anything on it, because practically anything you try to put on it will become fuel.

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