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Neuro-
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Nobody mentioned VX, the most toxic man-made substance, also maitotoxin (2nd most toxic) which looks like the most complicated non-peptide toxin. In
terms of man-made and complicated I might say vitamin B12 (cobalmin).
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careysub
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Quote: Originally posted by Neuro-  | | Nobody mentioned VX, the most toxic man-made substance, also maitotoxin (2nd most toxic) which looks like the most complicated non-peptide toxin. In
terms of man-made and complicated I might say vitamin B12 (cobalmin). |
VX is not nearly the most toxic man-made substance, not even the most toxic man-made chemical. Some radiotoxins are far more toxic substances
(e.g. Po-210) poisonous at the level of tens of nanograms.
Even at the time that the V nerve agents were being developed in the 1950s there were more toxic AChE inhibitors known, particularly a series of
carbamates. But they were not volatile at all, thus making them unsuitable for "nerve gas" use.
Probably the most potent AChE inhibitors ever discovered reside in Russian labs, developed during their super-secret biochemical weapon "Manhattan
Project" run during the 1970s through the end of the 1980s.
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DraconicAcid
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No, helium is smaller. Atomic radius 31 pm instead of 53 (webelements.com).
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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aga
Forum Drunkard
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Please try to revive Old threads with useful, new, accurate and relevant information rather than pointless kak.
Yes, you're 'still here' obviously, and that's fine, just try to get with the program : do some Science, preferably Chemistry, then we'll all talk
about That, you, what you're doing etc etc for ages.
[Edited on 26-1-2016 by aga]
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Neuro-
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| Quote: Originally posted by careysub | | Quote: Originally posted by Neuro- | | Nobody mentioned VX, the most toxic man-made substance, also maitotoxin (2nd most toxic) which looks like the most complicated non-peptide toxin. In
terms of man-made and complicated I might say vitamin B12 (cobalmin). |
VX is not nearly the most toxic man-made substance, not even the most toxic man-made chemical. Some radiotoxins are far more toxic substances
(e.g. Po-210) poisonous at the level of tens of nanograms.
Even at the time that the V nerve agents were being developed in the 1950s there were more toxic AChE inhibitors known, particularly a series of
carbamates. But they were not volatile at all, thus making them unsuitable for "nerve gas" use.
Probably the most potent AChE inhibitors ever discovered reside in Russian labs, developed during their super-secret biochemical weapon "Manhattan
Project" run during the 1970s through the end of the 1980s. |
Thanks for the clarification, I wasn't
including Novichok agents due to the ambiguity, but I didn't know about carbamates.
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Maker
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I've heard of azidoazide azide as being the most unstable, compound. Not really sure about that though, no Wiki page  .
As far as I know, Palytoxin is the longest carbon chain, biggest molecule ever fully synthesised and most toxic non-protein molecule.
[Edited on 26-1-2016 by Maker]
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aga
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Talking to yourself again ?
Don't worry, some mug will Engage, then you'll get what you're here for : Attention.
Just do some Chemistry, then you'll get all the attention you clearly Need.
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Amos
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aga, you're losing touch with reality.
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Big Boss
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Hmm. Excellent work, Mr Holmes.
Another mystery solved by the great forum drunkard. Who would have thought that all new accounts on this forum are in fact Little Ghost?
Keep up the good work big guy!
Kept you waiting, huh?
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Doctor Cat
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3-Nitrobenzanthrone
One of the most carcinogenic compounds known today
Also, according to wikipedia... monomethylhydrazine scores 4/4/4 in NFPA
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sclarenonz
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https://en.wikipedia.org/wiki/Ricinus
ricinus comunis
the most inexpensive, easy compound is obtained, it is easy to extract
and the plant exists on every continent:
https://pt.wikipedia.org/wiki/Mamona
breaking bad 
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Neuro-
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| Quote: Originally posted by Maker | I've heard of azidoazide azide as being the most unstable, compound. Not really sure about that though, no Wiki page .
As far as I know, Palytoxin is the longest carbon chain, biggest molecule ever fully synthesised and most toxic non-protein molecule.
[Edited on 26-1-2016 by Maker] |
Nope, it's second to maitotoxin at least in toxicity, longest carbon chain?
try polyethylene or some other polymer, and complexity's a bit subjective.
[Edited on 26-1-2016 by Neuro-]
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aga
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"We are what we think.
All that we are arises with our thoughts.
With our thoughts we make the world.
Speak or act with an impure mind
And trouble will follow you
As the wheel follows the ox that draws the cart."
Quote from Buddha, who spent more time thinking about it than i ever did, dunno about you.
As far as i can tell using the immediately available metrics, my average mind state has been fairly stable over the past 7 years.
Appologies for lampooning your Username in my sig for a day.
Clearly that caused you some lasting trauma, for which i should make ammends.
What would suffice ?
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Amos
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I think you're taking this a bit too literally.
| Quote: |
"...Speak or act with an impure mind
And trouble will follow you."
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You seem to be running into a lot of resistance from other members lately, wouldn't you say?
[Edited on 1-27-2016 by Amos]
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ScienceHideout
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I must say, if there is one thing that irritates me the most about general/physical chemists it is their inability to a) come up with a good
definition for atomic radius and b) define it precisely enough so that there is only one repeatable experimental value for the atomic radii.
Almost EVERY infographic you see on google images of 'atomic radius' shows something completely different. Some of them have helium smaller, others
hydrogen. For all intents and purposes, it is logical to list helium as the smallest because it corresponds to the trend that we all learned in high
school that 'atoms get smaller as you go right!' However, in my 2013 copy of the CRC Handbook, it lists hydrogen as not only smaller, but considerably
smaller. H being .32 A, and He being .37 A. Not only this, but it seems that chlorine is a small amount smaller than argon, fluorine is smaller than
neon, etc. It seems as if complete energy levels tend to throw off this periodic trend.
All this really irks me.
What is smaller, then? The CRC Handbook, basically my second bible, says hydrogen is. Countless credible internet sources say that helium is the
smallest. Is there a right answer? I doubt it. 
hey, if you are reading this, I can't U2U, but you are always welcome to send me an email!
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blogfast25
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| Quote: Originally posted by ScienceHideout |
What is smaller, then? The CRC Handbook, basically my second bible, says hydrogen is. Countless credible internet sources say that helium is the
smallest. Is there a right answer? I doubt it. |
Due to the quantum physical nature of atoms they don't have a well defined border, see e.g the radial probability distribution of a 1s (ground state)
hydrogen orbital:
http://hyperphysics.phy-astr.gsu.edu/hbase/hydwf.html#c1
Fuzzy balls don't have precise radii:
http://winter.group.shef.ac.uk/orbitron/AOs/1s/e-density-dot...
[Edited on 27-1-2016 by blogfast25]
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annaandherdad
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Blog is right. The electron density dies off gradually as you move away from the nucleus, so strictly speaking there is no radius beyond which there
is no more electron density.
It may be that part of the ambiguity about which atom is larger or smaller has to do with the arbitrary nature of various definitions of the atomic
radius. For example, you could define the atomic radius as the radius averaged over the electron distribution; or as the radius within which 90% of
the electron probability lies; or some other definition. These might give different comparisons between atoms (hydrogen vs helium etc). I don't
know, it would depend on the definitions being used.
However, I think there are arguments that helium is smaller than hydrogen, in their ground states, I mean. In both hydrogen and helium, the ground
state wave functions are 1s, but the nuclear charge in hydrogen is 1 and the effective charge in helium is between 1 and 2. It is not exactly 2
because the two electrons partially screen the nucleus. By one measure (a simple variational calculation) the effective charge in helium is 1 11/16.
So this would make helium smaller than hydrogen by this ratio. But this is only a certain approximation to true helium (not too bad, but not super
great either). This is explained in my notes on helium,
http://bohr.physics.berkeley.edu/classes/221/1112/notes/heli...
see the table in Sec. 12.
Any other SF Bay chemists?
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DraconicAcid
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The problem is that hydrogen atoms can't be lined up in a nice crystal for an X-ray or neutron diffraction study. They keep forming molecules.
Helium doesn't do that. So the radius of hydrogen is generally measured as a covalent radius (half the H-H bond distance) and that of helium would be
the inter-atomic distance in solid He. Of course they aren't comparable.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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JJay
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We can't forget nitrogen, which is the most abundant gas on the planet. I believe that silicon dioxide is the most abundant compound. The most
abundant liquid... I think that's molten iron, although water is the most abundant liquid compound.
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kecskesajt
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Diazotetrazole isn't friendly, too. 1% solution of it at 0 °C could detonate for no reason. Or if there is a reason: Someone breathed in the other
room.
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The_Davster
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With diazotetrazole it does not cause spontaneous detonation of the entire solution above 1%. It has such a low solubility that as its concentration
increases, it comes out of solution and the crystals spontaneously detonate when they do.
So one gets repeated, loud, detonations of the contents of the reaction vessel   That may break the glass and cause it to spill everywhere.
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Theoretic
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HIGHEST HEAT CONDUCTIVITY:
Not copper of course (400 W/(meter*Kelvin) at rt)
99.9% C-12 isotopically enriched diamond: 41,000 W/(meter*Kelvin) at 104 K, and 3,320 at rt (observed),
99.999 C-12 isotopically enriched diamond: 200,000 W/(meter*Kelvin) at 80 K (predicted),
and superfluid helium: here given as 3000 times oxygen free Cu at room t. Making it 400*3000=1,200,000 W/(meter*Kelvin). Although at heat flows over ~0.1 W/cm^2 it's not
in W/(meter*Kelvin) anymore, but proportional to the cubic root of the temperature gradient. The mechanism and magnitude are quite sensitive to the
temperature.
Back at room t, diamond is surprisingly matched not only by graphene/in-plane pyrolytic graphite, but also by cubic BAs (all ~2000 W/(meter*Kelvin).
All boron pnictides are higly heat-conductive, and could benefit from further isotopic enrichment of constituent elements (as well as being more
CVDable and thus compatible with the chip they're cooling, than graphite/diamond). Plus points for taking everyone by surprise.
STRONGEST MATERIAL:
Possibly not graphene (130 GPa) anymore, borophene could be stronger.
BEST CONDUCTOR:
Was (ironically semimetallic) graphene, borophene is probably better because it's fully metallic.
STRONGEST POISON (if you're a prokaryote)
Enediynes. A single molecule enters the cell and DSBs (double strand break) the DNA, the DNA circle opens and is irrepairable.
STRONGEST ODOR/FLAVOR:
Grapefruit thiol. 0.1 ppt by taste, 0.02 ppt by smell
[Edited on 23-4-2016 by Theoretic]
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crystal grower
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| Quote: Originally posted by JJay | | We can't forget nitrogen, which is the most abundant gas on the planet. I believe that silicon dioxide is the most abundant compound. The most
abundant liquid... I think that's molten iron, although water is the most abundant liquid compound. |
Actually, the most abundant mineral on the earth is probably bridgmanite, according to this:
http://www.smithsonianmag.com/smart-news/most-abundant-miner...
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Theoretic
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The LEAST common mineral:
"Until recent years jadeite has been something of a mystery mineral, but we now know of primary sources in Guatemala as well as several California
occurrences of white or grayish jadeite. Boulders in which a few small freestanding crystals have been seen occur in San Benito Co., California, with
additional finds in Clear Creek, between New Idria and Hernandez. All Mexican jadeite is in artifacts, from unknown sources. The record price for a
single piece of jadeite jewelry was set at the November 1997 Christie's Hong Kong sale: Lot 1843, the "Doubly Fortunate" necklace of 27 approximately
.5 mm jadeite beads sold for US$9.3 million."
[Edited on 27-4-2016 by Theoretic]
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crystal grower
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| Quote: Originally posted by Theoretic |
The LEAST common mineral:
"Until recent years jadeite has been something of a mystery mineral, but we now know of primary sources in Guatemala as well as several California
occurrences of white or grayish jadeite. Boulders in which a few small freestanding crystals have been seen occur in San Benito Co., California, with
additional finds in Clear Creek, between New Idria and Hernandez. All Mexican jadeite is in artifacts, from unknown sources. The record price for a
single piece of jadeite jewelry was set at the November 1997 Christie's Hong Kong sale: Lot 1843, the "Doubly Fortunate" necklace of 27 approximately
.5 mm jadeite beads sold for US$9.3 million."
[Edited on 27-4-2016 by Theoretic] |
To be accurate isn't astatine thought to be rarest mineral?
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