superpowerful explosive

[the_wingman]

I don't think anyone of us is able to make this stuff. But it's interesting anyway.
Imagine, 6 times as powerful as TNT..

[the_wingman]

oooops, I forgot to post the link, sorry..

http://www.newscientist.com/news/news.jsp?id=ns99991103

[FadeToBlackened]

Does anyone besides me think maybe he meant silicone, not silicon? Silicone has the structure:
*H****H
-Si-O-Si-
*H****H
well you get the idea.
This is made from some form of silane gas (SiH4) i think they change it to SiCl4. They are efficient fuels, but i think boranes are better. Diborane (B2H6) is an example but if you could get a solid by polymerizing it or something then i think that would be the way to go.

[This message has been edited by FadeToBlackened (edited August 03, 2001).]

[cutefix]

I think its elemental silicon with a monomolecular layer of hydrogen adsorbed in the surface.I am surprised that at cryogenic temperatures the reaction was violent to be estimated to be 8 times more than TNT.Common sense however dictates that a hot item in contact with a cold material will create a reaction that is usually vigorous.It looks like some form of catalysis occured in this silicon environment, for such a spectacular release of energy was achieved.Somehow for the time being I do not see any practical value,unless the true mechanism of this reaction is understood.Silicon is a unique material and had peculiar characterestic that make it suitable for semiconductors and solar cells.I forsee a vast potentials for this novel reactions.
Silicon as a fuel is said to improve rocket propellant performance,therefore there is apossibility that it will improve also the explosive performance of future explosive formulations.

[This message has been edited by cutefix (edited August 05, 2001).]

[Microtek]

Did you notice that line where it said
"releases seven times as much energy as TNT, and explodes a million times faster."

Seven times as much energy is just about twice as much as NG, which is credible, but a million times faster thats about 20 times the speed of light. The question is if this information is totally erroneous or if they mean something quite different from what they say.

[-A-]

I am a little confused with the article...
Fist of all, what the f*** is porous silicon???. In the article says this: "Porous silicon has a layer of hydrogen just one atom thick covering its surface.". Hydrogen??? where in hell does the hydrogen comes from???.
Second, why is that silicon gets oxidised at very low temperatures?. They don't give an explanation for the reaction.
It also says this : "And using liquid oxygen rather than gas means there are lots of oxygen atoms at the silicon surface". who talked about using liquid oxigen? that's an idea they have?. It sounds a little suicidal too...
Oh, and I agree with you. A million times faster than TNT???. Haha, Einstein was wrong... Who wrote that article???

[Lagen]

<font face="Verdana, Arial" size="2">The group had cooled the silicon in a vacuum to the temperature of liquid nitrogen, when suddenly a leak in their equipment allowed air into the device. The silicon exploded. "We realised immediately that oxygen was condensing on the sample ..."</font>The LOX came from the air. There would really be more molecules of oxygen available and this may make it work, in a gaseous state the molecules are too far apart. BTW similar to coal/active carbon+LOX. Si and C have many similar properties.

[Anthony]

"explodes a million times faster."

Maybe it doesn't mean "million" as in 1 000 000 but as in "much" or "lot's". People often use "million" to describe something in excess, especially when they don't know the actual figure.

[fightclub]

They are right about: 7 times more energy because oxidation of Si to SiO2 (sand, quartz) gives around 7225 kcal/kg of Si (and that is what they are basing it on, the oxidation of Silicon), but now the balanced --mixture- of Si with O2 would deliver about
3189 kcal/kg (thus the explosive mixture is about 3 times more energetic than TNT) compared to:

Carbon/LOX based explosive: 2136 kcal/kg (equimolar)
TNT: like 900-1100 kcal/kg,
Nitroglycerin: 1480 kcal/kg,
the well-known Octanitrocubane falls short of 2000 kcal/kg.


And, I am unsure (it is hard to say) about the detonation velocity but it is probably in the range of 7000-10,500 m/s.

6.9 x 10^9 m/s (speed of light is 2.998 x 10^8 m/s) is a definite exaggeration. What they meant to say: "explodes faster than TNT!".
-

"We are not your job. We are not how much you have in the bank. We are not the car you drive. We are not the contents of your wallet. We are the all-singing, all-dancing crap of the world."

[This message has been edited by fightclub (edited August 08, 2001).]

[cutefix]

There are lot explosive power comparison that they base on the standard explosive like TNT.However if the comparison is against an abnormal explosive phenomena that occurs in nature,it only means of explosive yield.There are a lot of explosion that are not considered normally as fast explosion but it still able to come-up with much energy.Just think of this Fuel- Air Explosives;it is estimated that its power is equivalent to five times that of TNT.If you look at it closely,it is unable to produce the detonation velocity of the standard explosive.However the resulting power it produces from the exploding fireball is enormous and can surpass that particular chemical explosive....

[Microtek]

Fightclub: Are You sure that the energy of explosion that You posted for TNT is correct?
I seem to remember a figure around 2700 KJ/Kg
( 1000 Kcal = 4186 KJ ).

[fightclub]

Heat of explosion values.

[megalomania]

They probably meant it reacts a million times faster (as in reaction rate) and not it has a million times the explosive velocity. On these terms a factor of a million isn't all that much.

Submitted for your approvial, I just happen to have the article written by Dr. Kovalev around here somewhere... sonabitch I can't get remote access, but I do have some more details until I can get to the local university in person.

Title: Strong Explosive Interaction of Hydrogenated Porous Silicon with Oxygen at Cryogenic Temperatures

Authors: Kovalev, D.a; Timoshenko, V. Yu.a; Künzner, N.a; Gross, E.a; Koch, F.a

Affiliations: a. Technische Universität München, Physik-Department E16, D-85747, Garching, Germany

Abstract: We report new types of heterogeneous hydrogen-oxygen and silicon-oxygen branched chain reactions which have been found to proceed explosively after the filling of pores of hydrogen-terminated porous silicon (Si) by condensed or liquid oxygen in the temperature range of 4.2—90 K. Infrared vibrational absorption spectroscopy shows that, while initially Si nanocrystals assembling the layers have hydrogen-terminated surfaces, the final products of the reaction are SiO2 and H2O . Time-resolved optical experiments show that the explosive reaction develops in a time scale of 10-6s . We emphasize the remarkable structural properties of porous Si layers which are crucial for the strong explosive interaction.

Publisher: American Physical Society

This is from Vol: 87, Issue: 6, August 6, 2001 of Physical Review Letters.

While I am on the topic of looking at journals, I have the power to get just about any article one could want. Why here is a goody, the Journal of Propellants, Explosives, and Pyrotechnics: This international journal provides a vital forum for the exchange of ideas in the areas of propellants, explosives, primers and pyrotechnics, and combustion and detonation processes. Its coverage of propellants and explosives includes their preparation, investigation, analysis, testing and evaluation. Results of theoretical or practical investigations into combustion and detonation processes such as internal ballistics of guns and rockets or high-explosive ballistics are also included.

Kind of sounds like what we do here http://theforum.virtualave.net/ubb/smilies/smile.gif I should reprint this in the intro.


------------------
For the most comprehensive and informative web site on explosives and related topics, go to Megalomania's Controversial Chem Lab at http://surf.to/megalomania

[This message has been edited by megalomania (edited August 10, 2001).]

[wantsomfet]

http://www.e16.physik.tu-muenchen.de/e16html/research/optik/optik.de.htm

This is the homepage of the "inventors". Click the link at the bottom of the page to see a video of a 6mg (!!!) sample.

------------------
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[PrimoPyro]

This is very simple electrochemistry as work here.

First of all, they do mean silicon, as in the elemental form of silicon. Porous silicon, like they said, has an unbelievable quantity of nanoscale holes in it's molecular structure. The silicon itself is crystallized in the cubic system IIRC, just like carbon. But the (much) lower electronegativity of silicon, and the further atomic radii of its valence orbitals, creates a much higher energy output when it combines with an electronegative molecule like diatomic oxygen, than say the same reaction with carbon would.

As the oxygen comes into contact with the PURE silicon, the highly energetic state of the electrons is disturbed. They are easily torn from their orbitals in a very rapid reaction with the oxygen. The corresponding orbital rearrangement involves electrons cascading to lower energy states at a very rapid rate. This energy must go somewhere. Guess where?

Combine this with the scenario of LIQUID oxygen being involved, and you get this monstrous explosion. The thermal energy (cryogenic temperature) has nothing to do with the energy output. Liquid oxygen has over 600 times the available oxygen content per volume than gaseous oxygen. At this pressure-volume configuration of only standard atmospheric pressure and such incredible density, equilibrium STRONGLY favors dissipation/expansion. The oxygen literally rips through the silicon molecule invading all its crevices with strong force.

As for the cryogenic temperature, the specific heat of oxygen and silicon is not high at all compared to heavier elements such as iron and above, and it takes minimal energy to raise their temperature. The sheer energy release/mass to absorb it ratio is so high that those temperatures mean nothing with such a small mass and high surface area.

BOOM.

PrimoPyro

[Mr Cool]

Also, you'd get lots of lattice energy released when the SiO2 condenses, like when you burn Al or Mg, which you don't get with C.
I've heard that blocks of porous Al (produced from Al powder and a small amount of some sort of binder, I guess) are used as a sort of binary with LOX in some applications, anyone got more info on this?

[Chris The Great]

I checked the site (it moved around a bit, the new link is http://www1.physik.tu-muenchen.de/~dclement/silanz/index.htm click on resultate) and it apperantly only has a detonation velocity (at least what I assume is a det. velocity, I have no clue what any of that says, I just picked familiar words) is only 2.5km/s. I'm guessing this is because the oxygen must travel to get at the silicon.

Temperature is estimated at 6750K :eek:

Wow....

[vurr]

"durch die große inner Oberfläche enthält 1 cm3 mikro-poröses Si etwa 10E22 Wasserstoff-Atome an der Oberfläche (in der Gasform entspräche das etwa 1,2 l H2-Gas"
1.2 litres of hydrogen in 1cm^3...????
+LOX.
+porous Si
nice mix.

[Jacks Complete]

Is this really news, though?

You take almost anything at room temperature, add LOX, and you get a damned fast burn.

Iron burns in air if you divide it finely - just stick a 9v battery into it, or a match. Corn flour will explode as a dust, just in the atmosphere, which is gaseous and only about 21% oxygen.

Combine the two, and *surprise* you get an even faster burn.

You can do the same with any finely divided fuel, and LOX. The real trick would be to take the LOX and soak the fuel in it *without* it going pop, and then being able to set it off when you wanted, rather than just on contact. This would allow far better conversion of the available fuel, and hence far more powerful explosions.

You can make this stuff really easily, too. Just work out where to buy LOX from, then make yourself the porous silicon. You make it by taking some silicon, and dissolve the impurities out with acid. Not difficult.

http://www.bath.ac.uk/physics/groups/ppmg/research_psi.html

Etching Technique

Nanoporous silicon is made by passing electric current through silicon that is in contact with a strong acid solution. An acid "front" nibbles away into the silicon and as it advances it leaves behind a sponge-like structure that is full of linked passages or "pores". The pores are only about ten nanometers across; that is, they are only about twenty silicon atomic spacings wide (compared to the lattice parameter of the silicon wafer) and so small that not even a 'flu virus could fit in them. The current used controls the fraction of silicon that dissolves where the front of acid has reached, so by varying the current as the etching progresses we can vary the porosity from place to place. Thus, we can design and control the exact porosity profile of a sample.

This shouldn't be too hard to do at home.

[nbk2000]

I wonder how well uranium hexafluoride atoms would fit through such silica nanopores, and at what rate would the 235 pass through compared to the larger 238, seeing as how easily it's made at home (the silica filters)? ;)

[Marvin]

Nice idea but I would suspect it would effuse, to diffuse the pores need to be of comparable size to the molecules. I would also expect it to attack the silicon.

[Jacks Complete]

Which, given the rate of reaction with LOX, could be pretty impressive!

Radioactive liquid gas that explodes like a huge bomb, as the fluorine reacts with the silicon *even faster* than the LOX?

Dirty nuke?

[Pb1]

The problem with NBK’s idea is that UF6 is extremely reactive. In fact, one of the few materials they could use to enrich the uranium was Teflon because it’s so inert. It will undoubtedly destroy glass, so silicon would definitely not work.

[FUTI]

Al is often used in rocket fuels IIRC buster rockets use it in combination with ammonium-perchlorate...is something similar posible with Si?