When I was a kid, I wanted to be a scientist. First an astronomer (I had lots of children-friendly books on the subject), then a chemist. It didn’t pan out for several reasons but I’ve kept a distant interest, and sometimes when I’m bored I read Wikipedia pages dedicated to chemical compounds I’m not familiar with, hoping to find some exotic properties. Alas, this is hit or miss and, more often than not, what I stumble on is “colourless” and “odourless”. Boring.
I’m already familiar with Derek Lowe’s Things I Won’t Work with and that blog has filled many of my afternoons with joy, even if some of it is a bit over my head.
So, I turn to you to provide me with examples of chemicals with remarkable properties that people who haven’t done chemistry since secondary school can understand. I’ll post this here since I’m looking for factual answers but it could IMHO.
Methanethiol (Mercaptan) - The additive to natural gas and propane so you can smell a leak. Also, the one responsible for bad breath, flatus, asparagus pee, swamp gas, pulp mill pollution, etc…
The gas dinitrogen tetroxide (N[sub]2[/sub]O[sub]4[/sub]) is colorless and odorless… but wait, there’s more. It only exists at low temperatures and/or high pressures; at normal temperatures and pressures it spontaneously converts to two molecules of nitrogen dioxide (NO[sub]2[/sub]), which you’re familiar with if you’ve ever been to Los Angeles: It’s why the air there smells bad and looks brown.
Probably not what you mean, but phosgene has a new mown grassy smell, and a hint of that metallic taste like when you hold a handful of coins in a hot sweat hand … and chlorine gas can be seen as a pale green cloud.
One of the classic chemicals from the chemistry sets of my youth is Cobalt Chloride. As with many chemicals, there is a plain form and not one but at least two hydrated forms. In many cases it’s hhard to transition between the two, but cobalt chloride does so very easily – a change in room humidity can do it. The different hydrates have very different colors. The anhydrous form is blue, the dehydrate is purple, and the hexahydrate is pink. One experiment the chemistry kits had was to make a “weather indicator” by painting a patch of paper with cobalt chloride solution, or soaking a piec of cotton in the solution. In dry weather, it’d be blue. In humid weather, it’d be pink-purple.
Nowadays they put some in dessicants to indicate if it’s absorbed water or not.
Nitrogen tetroxide was used as an oxidizer in some of our exotic engine tests at NASA in the 1960s. When it was vented it made a brown-reddish cloud we had to be on alert for. I only saw it once and we all ran like hell to get back in a building.
They only ran those tests on second shift and we all were issued gas masks to carry around. Actually we had our masks sitting on a curb outside and when the red cloud swept over our building and came towards us our crew chief grabbed them all and yelled, “Run!” We just ducked in the nearest door and shut it.
YInMn Blue is the name for a new blue pigment that was recently discovered at Oregon State. It’s apparently the first new inorganic blue pigment in about 200 years.
Benzeneselenol… smellin’ good… (one description: “imagine 6 skunks wrapped in rubber innertubes and the whole thing is set ablaze. That might approach the metaphysical stench of this material.” It’s also toxic, natch.
Colours… how about Tyrian Purple? Got to harvest hundreds of thousands of Murex snails to make that one.
It’s just one of the mercaptans. There are others.
IME, the best way to sample the full range of them, as well as a variety of other truly delightful odoriferous compounds? Have a good whiff oflandfill leachate.
<narrator: this is not a good idea>
Someone working on leachate for a project opened a container of some in a talk he was giving to our Geochemistry class. People at the *back *of the lecture hall (including me) were retching.The faculty was not amused. That was truly the worst thing I’ve ever smelled in my life.
But don’t get any on your fingers. It turns into brown manganese dioxide and it will not come off. You will walk around for a week or two looking like you have poop on your fingers.
Yes Esters - the salts of the organic world - they determine the price of wine and spirits.
When fermenting, yeast produce varying amounts of organic acids which taste terrible. Organic acids react with alcohol albeit very slowly to make esters which smell good and taste good. Hence the preference for aged wine and scotch and other liquors.
Wood barrels also have tannins and other acidic components which react with the alcohol to make esters - again sweet smelling / tasting. Hence the aging of alcohol in wood barrels.