[Djordje]

Acetone Peroxide - easy to make, did it once, unstable - 2 grams ignited by friction of paper bag it was in - friend got little burned
Aqua regia - solution of HNO₃ and HCl in proportion 1:3 - extremely corrosive (gold dissolves in it).

[Periodic Acid]

dihydrogen monoxide

[Ziconotide]

Cyanides are not dangerous...same thing for common reagents in the lab. Do you really want 2 know REALLY dangerous materials? So toxic, that one exposure 2 them can be deadly? I will give some examples of EXTRAORDINARY toxic materials:

Botulinum toxin

Ricin

Abrin

Diphteria toxin

Dimethyl mercury

Methyl isocyanate

Batrachotoxin

Aflatoxins

Taipoxin

GF nerve agent (cyclosarin)

GD nerve agent (soman)

Dimethyl sulfate

Saxitoxin

Aconitine

Palytoxin

Maitotoxin (extremely nasty)

These are the chemicals of Hell, deadly as Grim Reaper's scythe

[skwiff]

Ziconotide, on 26 September 2011 - 06:18 PM, said:

Cyanides are not dangerous...same thing for common reagents in the lab. Do you really want 2 know REALLY dangerous materials? So toxic, that one exposure 2 them can be deadly? I will give some examples of EXTRAORDINARY toxic materials:

Botulinum toxin

Ricin

Abrin

Diphteria toxin

Dimethyl mercury

Methyl isocyanate

Batrachotoxin

Aflatoxins

Taipoxin

GF nerve agent (cyclosarin)

GD nerve agent (soman)

Dimethyl sulfate

Saxitoxin

Aconitine

Palytoxin

Maitotoxin (extremely nasty)

These are the chemicals of Hell, deadly as Grim Reaper's scythe

palytoxin and maitotoxin are the most toxic non-peptide based toxins in existance... but the are spat on by botutoxin

[Anders Hoveland]

Dichlorine heptoxide, Cl2O7, is dangerous is several unusual ways.


95-100% Concentrated Perchloric Acid

Physical Properties

Pure perchloric acid is unstable. If left standing at room temperature for between 10 and 30 days, at some point the temperature of the acid will spontaneously rise to 90 degC, at which point there will be an explosion. Pure perchloric acid cannot be distilled at ordinary pressures. To avoid partial decomposition (into Cl2, O2, and various chlorine oxides), distillation must be done below 200 mmHg.

Reactivity

"I would expect CH2Cl2 to react with HClO4 (if not sooner, then later), since HClO4 seems to react with both CHCl3 and CCl4, and CH2Cl2 is less oxidized. I would be especially careful with CH2Cl2, it should easily be at least a detonable mixture.

Namely, HClO4 is entierly miscible with CHCl3, the solution discolors after a few days to yellow, and in air sheds crystals of HClO4.H2O. Commercial chloroform contains alcohol, which sheds a heavy, with CHCl3-insoluble extraordinarily explosive oil (Vorländer, v. Schilling, Lieb. Ann. 310 [1900] 374; Vorländer, Kaascht (Ber. 56 [1923] 1162).

For CCl4, HClO4 is insoluble in CCl4, and gives upon shaking, a green emulsion, which discolors brown after several minutes welling up under formation of HCl and COCl2 (Vorländer, v. Schilling, Lieb. Ann. 310 [1900] 374). Preparation of solutions of Cl2O7 in CCl4 described in: F. Meyer, Keszler (Ber. 54, [1921] 569).

the interaction of HClO4 with benzene has been described as follows:
If one to two drops of HClO4 has 2 to 3 cm3 benzene poured over it, under heat evolution brown flakes precipitate. Mixing of equal volumes at first forms a green emulsion, which then explodes (Vorländer, v. Schilling, Lieb. Ann. 310 [1900] 374). 1 g of HClO4 solubilizes in 5g of well-cooled benzene under formation of a green solution, which when stored in a sealed tube, discolors increasingly shedding a carbon-containing material; after completion of the reaction, no free acid is found anymore (Michael, Conn, Am. chem. J. 23 [1900] 444).

So mixing something like CCl4 and HClO4 can cost one their lives if not wearing protective gear, doing under fume hood,etc. It is dangerous to extrapolate so assuredly."


Dichlorine Heptaoxide (perchloric anhydride) Cl2O7

Physical Properties
Cl2O7 melts at (minus) -91.5 degC and boils at 80 degC. At 0 degC, it has a vapor pressure of 23.7 degC. Cl2O7 has a density of 1.86 g/mL. Cl2O7 decomposes spontaneously on standing for a few days. Cl2O7 decomposes into chlorine and oxygen under very low pressures (below 80mm Hg) or in the temperature range of 100-120 degC. Cl2O7 is soluble in benzene, slowly attacking the solvent with water to form perchloric acid. Cl2O7 detonates when heated or when subject to mechanical shock. It explodes on contact with flame or by percussion.

Chlorine heptoxide is more stable than either chlorine monoxide or chlorine dioxide; however, the anhydride detonates when heated or subjected to shock.

Reactivity
Cl2O7 is soluble in benzene, slowly attacking the solvent with water to form perchloric acid; it also reacts with iodine to form iodine pentoxide.”

Benzene reacts with Cl2O7 However this seems to contradict something else I read. "Cl2O7 is a strong oxidizer as well as an explosive that can be set off with flame or mechanical shock, or by contact with iodine. Nevertheless, it is less strongly oxidising than the other chlorine oxides, and does not attack sulfur, phosphorus, or paper when cold."
Holleman, Arnold F.; Wiberg, Egon (2001). Inorganic chemistry. Translated by Mary Eagleson, William Brewer. San Diego: Academic Press. p. 464. ISBN 0123526515.
^ Byrns, A. C.; Rollefson, G. K. (1934). Journal of the American Chemical Society 56: 1250–1251.

So Cl2O7 reacts with benzene, but not paper or phosphorous when cold? One explanation might be that a protective layer is formed that prevents further oxidation. P2O5 is known to form an adhesive layer on reaction with water that limits further hydration, for instance. However, failure of Cl2O7 to react with sulfur cannot be explained by a protecting layer, since nothing could form that would not be soluble or a gas. HNO3 attacks sulfur, but not benzene, so I have difficulty believing that Cl2O7 would react in an opposite way. Thus this is all quite confusing, and to make any sense of the conflicting references is a logic puzzle.

Cl2O7 does not explode on contact with wood, paper or similar materials but just evaporates (Michael, Conn, ibid). They also note unreaction towards sulfur and phosphorus pieces. HClO4 on the other hand does explode violently on contact with wood and paper, and especially charcoal (Roscoe, Lieb. Ann. 121 [1862] 353).

Cold, dry C6H6 solubilizes Cl2O7, then soon afterwards a reaction occurs (A. Michael, Conn, Am. chem. J. 23 [1900] 446).

Cl2O7 reacts with iodine to form iodine pentoxide (I2O5). Addition of iodine to Cl2O7 can result in explosion, however, so the reaction is probably best done diluted in an appropriate solvent.


Other compounds related to Cl2O7

Perchloryl fluoride (FClO3) is very stable, poisonous and reactive (Bp. -46.7C, Mp. -147.7C). Electrolysis of satd. NaClO4 in anhydrous HF yields the compound. Another way in 85-90% yield, is to warm a mixture of KClO4, HF and SbF5 at 40-50 C (Kirk Othmer). FClO3 is also stable up to 400 C, and hydrolyzes slowly. Grease and rubber tubing has caused explosions, for more reactivity see Brethericks.

The German wikipedia claims alkali fluorides reacting with Cl2O7 does yield FClO3, though no exact reference is given for this.

Hantzsch claimed to have made fluoronium perchlorate [FH2]ClO4 by reacting anhydrous HClO4 with anhydrous liquid HF, which under strong heat evolution was said to yield solid [FH2]ClO4 (Ber. 60 [1927] 1946), and which compound he said reacts explosively with H2O (Ber. 63 [1930] 97). Brauer and Distler (Z. anorg. u. allgem. Chem. 275 [1954], 157) tried to make this compound, but could not repeat preparation despite mixing in various ratios and temperatures.

FClO3 is also made by reacting fluorine with KClO3 at -20 C in SbF5: KClO3 + F2 = KF + FClO3 Or by reacting KClO4 with HSO3F: KClO4 + HSO3F = FClO3 + KHSO4 (From: Lehrbuch der anorganischen Chemie by A.F. Holleman, E.Wiberg, N.Wiberg). On the last one, no more decent details given by Holleman et al., it could react right away or may need some warming, time to hit the more serious lit.

With ammonia, FClO3 forms a perchlorylamide: FClO3 + NH3 = ClO3(NH2) + HF. This has acidic protons and they are replaceable by metal ions: K[ClO3(NH)] and K2[ClO3N] these are colorless, up to 300 C stable compounds, which explode by impact.

"Dichlorine hexoxide is a dark red fuming liquid at room temperature that crystallizes as an ionic compound, chloryl perchlorate, [ClO2]+[ClO4]−. Many other reactions involving Cl2O6 reflect its ionic structure, [ClO2]+[ClO4]−, including the following:
NO2F + Cl2O6 → NO2ClO4 + ClO2F "

[mskittykat]

Haven't seen anything half as impressive as the stuff on this list...don't know if I should be happy or not

Just the usual suspects:
Conc HCl, H2SO4, conc NaOH, ether

[Mrl4]

It was sulfuric acid (concentrated) that I had to pour into a very narrow container WITHOUT ANY GLOVES. My lab partner didn't dare to do it so I did. And we needed to do this in 3 experiments... :S

[Freb T Fische]

I'm a first year chemistry student, So I've only done General Chemistry 1...

But I'd probably have to say either solid NaOH, or Concentrated Sulfuric acid... Rather tame, but first year chem student.

Now I have watched some videos on YouTube that contain some pretty nasty stuff i.e. elemental Flourine, but I don't think that counts.

[Anders Hoveland]

Sodium methoxide is really dangerous. It is a highly corrosive liquid, more basic than sodium hydroxide.

It has the unique charactaristic that if a few drops get splashed onto skin it will cause chemical burns but will deactivate pain receptors so that one may not realise that they are being burned. I have poured concentrated HNO3 before, and often I feel little points of burning on my skin from the little micro-droplets that splash up into the air, even when pouring very carefully and there is no obvious splashing. Sodium methoxide is also very flammable, and if one tries to extinguish the fire with water, it will just generate much heat as the water violently reacts with the substance, causing methanol to boil out and causing a big fire cloud to form.

[CharonY]

Quote

It has the unique charactaristic that if a few drops get splashed onto skin it will cause chemical burns but will deactivate pain receptors so that one may not realise that they are being burned

I wonder whether that is true. I read on wiki that it is supposed to kill nerve cells, which would indicate extreme and rapid neurotoxicity. However that did not appear to be what the MSDS sheets indicate. Do you happen to have a source for that?

Also I would have assumed that one would wear PPE when pouring HNO3. Just saying.

This post has been edited by CharonY: 21 April 2012 - 02:06 AM

[radioactive cookie]

I did regular chemistry my sophomore year of highschool, and now, during my senior year, I'm about to finish AP chemistry, which is one of the college level classes offered at my school. Like first year chem students, I have not seen or handled half of these dangerous-sounding chemicals listed here.

I've handled the common stuff. We had a lab where 16 M HCl was used, concentrated NaOH, and various other skin irritants and the like.

Before one lab, my teacher informed the class that one of the chemicals we'd be handling was a known carcinogen that definitely shouldn't be inhaled. I wish I could remember what the chemical was called... I believe the carcinogenic chemical was the small solution we made by dissolving blue-to-purple copper II chloride crystals in a certain alcohol.

In my own time, I did do electrolysis of sodium chloride solution. All I had to do was use two ordinary 1.5 volt batteries with a couple of good electrodes, and I got a little chlorine gas. Can you really get chlorine with just two double A, 1.5 V alkaline Duracell batteries, or was my light green solution something different? =o I was wondering, because the videos and online instructions I've read always use 9 volts or higher.