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Derek Lowe mentions dimethyl mercury as the first substance that's not worth the risk: https://www.chemistryworld.com/opinion/a-risk-not-worth-taki...
Earlier quoted context omitted.
The density of Dimethyl Mercury is almost 3g/ml, so 0.1 mL is like 300 mg. From https://en.wikipedia.org/wiki/Cyanide_poisoning > A fatal dose for humans is on average 1.52 mg/kg of body weight Assuming 80kg(175pounds), that's like 120mg of Cyanide. There is probably even more nasty stuff.
well, easily. any organophosphorus stuff for example.
You may also be thinking of phosgene, which actually contains no phosphorous at all. But it is extremely toxic see the LC50: https://en.wikipedia.org/wiki/Phosgene
Can someone who knows a thing or two about chemistry explain why one would need to synthesize or purchase this chemical. Given that it involves a student I'll take "because of bragging rights to impress everyone" as a valid response, but wondering if it has any value is otherwise? Is it one of those "well despite its danger it's still the best at X, Y and Z and nothing else comes even close"?
If you’re testing for dimethyl mercury in say fish, you need a standardized sample of dimethyl mercury to run.
These references are highly dilute and thus less hazardous. But some labs prepare their own references rather than buying them.
That requires working with pure dimethyl mercury.
The hazard is manageable as long as you’re prepared. Chemists work with lots of hazardous chemicals and it can all be managed with the right preparation.
Earlier quoted context omitted.
well, easily. any organophosphorus stuff for example.
Actually organophosphates are not that lethal. See the LD50 of this example: https://en.wikipedia.org/wiki/Malathion You may also be thinking of phosgene, which actually contains no phosphorous at all. But it is extremely toxic see the LC50: https://en.wikipedia.org/wiki/Phosgene
Earlier quoted context omitted.
Sorry I believe it was copper etching maybe, probably not glass. Been a while...
I'd think copper would mean ferric chloride, which isn't that bad.
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the methyl groups make it organic chemistry (and dangerous), elemental mercury is fairly safe
There was a time not so long ago when it was common for chemistry teachers to show off pools of mercury in their bare hands. By the time I first took chemistry classes, though, that practice had stopped, less out of concern of exposure to liquid mercury and more for accidental exposure to gaseous forms due to spills.
One way to familiarize students with mercury was to have several liters of it in a wide open-top jar and have them force their fist through the mercury pool to the bottom of the jar.
In fact, forcing one's hand through mercury between six to eight inches deep is not easy, some kids found it too difficult to do.
I'd describe my hand as feeling very squeezed and it being forced upwards to the surface with considerable force. The experience was certainly unforgettable.
There were some safety protocols: good ventilation (to minimize Hg vapor) and afterwards hands had to be thoroughly scrubbed with soap and water.
Other "sources" (using the word loosely as their provenance is unclear) > "based on the information available, this was a localized issue with only one student directly exposed. Their reported use of dimethyl mercury was unauthorized. MIT does not allow the purchase or synthesis of dimethyl mercury." [1] Karen Wetterhahn's exposure and death [3] is a cautionary tale of the extreme toxicity of dimethyl mercury, and wa…
Yes, dimethyl mercury is terrifying stuff - it killed Karen Wetterhahn from a few drops that went _through_ the gloves she had on: > The case proved that the standard precautions at the time, all of which Wetterhahn had carefully followed, were inadequate for "super-toxic" chemicals like dimethylmercury (from the Wikipedia page [3])
There aren't really any "good" organometals, but if there were, they wouldn't be this stuff.
Back in 1998, I scored a consulting job at a silicon plant outside of Salem, OR. Now I was working as a systems admin and I was expected to be responsible for the computer systems, which were basically located in the normal offices, rather than a dedicated machine room floor. However, since it was an active silicon manufacturing plant, all employees and contractors were obligated to complete safety training sessions.…
I think Hydrofluoric acid is probably the substance you're describing which leaches the calcium out of your bones. It will certainly burn you too though. It's a common byproduct from heating fluorinated gases and is sometimes used in its own right for wet etching. As an aside, I love it when they tell you in the safety WBT what the highly toxic gas smells like.
Other fun chemicals used in fabs were Silane (CSi4), methane w/ silicon instead of hydrogen, used to form a silicon dioxide layer for etching* w/ HF and final step of protection. It would spontaneously combust on contact with air, so when you popped a tank fitting it would leave a white powder residue. Silicon dioxide is used as a food additive so AFAIK that wasn't dangerous.
Phosgene was also used as a dopant. If the alarm for that went off you really got out ASAP.
Arsine was a dopant also.
This is what I sort of remember from working on slacker job in silicon fab a long time ago when the number of transistors per chip was 1. I did say a long time ago.
* You could also just oxidize the outer layer of the silicon wafer itself w/ water vaper at high temps.
Earlier quoted context omitted.
Actually organophosphates are not that lethal. See the LD50 of this example: https://en.wikipedia.org/wiki/Malathion You may also be thinking of phosgene, which actually contains no phosphorous at all. But it is extremely toxic see the LC50: https://en.wikipedia.org/wiki/Phosgene
This is not true, and choosing the LD50 of Melathion to represent organophosphates as a whole seems odd. He was probably thinking of nerve agents or perhaps pesticides. Take a look at the LD50's of the former. These are among the nastiest, most lethal substances known to man.