Tag Archives: Chemistry

Sh*t I wont touch – The Legendary Picric Acid

Picric acid sounds like something out of Harry Potter – and it’s original concoction is the stuff of legend. Picric acid was more explosive than TNT.

Boom! Credit to Wikimedia commons
Boom! Credit to Wikimedia commons

Johann Rudolf Glauber first proposed pycric acid in 1742. It was first made from animal horn, silk, indigo and a resin using a recipe that looked almost identical to the ingredients necessary to bring Voldemort his body again.

The military caught wind of this chemical and found that it was highly effective in artillery as it was shock proof. Previous explosives like nitroglycerine would sometimes detonate in the artillery barrel which wasn’t a happy ending for anyone. The British, French and Japanese started toying around with it and it formed the basis for the following boomers:

– Explosive D (US)

– Lyddite (GBR)

-Shimose powder (JAP)

– Ecrasite (AUSTRIA)

– Melinite (FRA)

Why was it so dangerous?

Over time water evaporates from the substance leaving crystalline salts behind. These acid crystals are highly volatile and explode readily under friction or a change in temperature. The crystals react with metals and alkaline materials very easily, such as contrete, to form an explosive picrate salt – this particular salt caused booms that were bigger than TNT.

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Picric Acid; Image credit to National Institute of Standards and Technology (NIST)

The sensitivity of picrate acids comes from the NO2 groups on the main body (similar to TNT) – under a reaction they combust releasing a significant amount of heat and energy. Here’s a video to see what can happen:

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Sh*t I Won’t Touch – Chlorine Azide

Today we’re looking at a bag of fun known as chlorine azide. Chlorine azide was highly reactive, toxic and unstable – it was only really useful for figuring out what would blow up first if you opened a jar of it.

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What happened to every chemist that tried to play with it …
[Image courtesy of http://hqwide.com/death-dark-gray-chemistry-background-chemicals-blackboard-wallpaper-46976/]

No, seriously, that’s why they’re used. Their essential character is to make stuff around them change. Never put something next to a jar of Chlorine azide that you’re not comfortable seeing re-arranged in a suddenly violent fashion. The real challenge with this compound is finding something it WONT react with violently.

An excerpt from the 1943 JACS article on chlorine azide:

Owing to the extreme instability of the compound accurate determinations of the boiling and melting points have not been made as yet. Numerous explosions, often without cause, have occurred during experiments.

Wikipedia describes it in a similarly fun way:

‘It usually detonates violently, whatever the temperature, without apparent provocation’

What’s interesting to note is its brother, Sodium Azide, saves lives every single year – particularly throuhg its use in older air bags in cars.

Why is it so dangerous?

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A lovely molecule of chlorine azide – it’s the green bond you want to worry about ….
[Image courtesy of ChemNet http://www.chemnet.com/cas/en/13973-88-1/CHLORINE-AZIDE.html]

Chlorine Azide – it’s that green single bond that is the reason why this little man will blow up without provocation

A strongly, electronegative, chlorine is bonded with a very, very fragile single bond to a triple bond in the nitrogen compound. End of days occurs when the chlorine wants to find a new partner. Because this single bond is very, very fragile, all it takes is a partial electropositive charge on a neighbouring atom or molecule to break the Cl-N bond. The chlorine lovingly elects to take the rest of the compound with it. It’s like a trip-wired explosive. Because of this charmingly violent feature, it has little use in the lab other than to investigate substances and find out how on Earth you can stop this from happening.

Sh*t I won’t touch! – Dimethylcadmium (Lucifer’s party starter)

This blog post is a first of many, I hope, in the field of dangerous chemicals. Here are a collection of my favourite little nasties I won’t work with in the lab. Today we’ll start of with a “simple” Cadmium compound and tomorrow we’ll look at something that explodes for absolutely no reason at all.

Ready? Let’s kick off with DIMETHYLCADMIUM!

Everyone knows about Lead and Arsenic etc. Did you also know that Cadmium is just as bloomin’ nasty?

Cadmium – our dangerous friend

I know, as an element, it looks so harmless – but don’t be fooled!. It has acute toxic effects (chemistry’s version of stabbing you – quick acting), and it has chronic toxic effects (ruins you long term).

A Wall of Flame


Lucifer running for a jar of Dimethyl Cadmium
 Image courtesy of 123RF -(Licensed to Creative Commons)

Dimethyl Cadmium would be the stuff that Lucifer uses to start a bonfire. It’s basically the demon compound of the organometallic world. An organometallic compound is a compound where carbon and metal are bonded together, largely through covalent bonds.

Dimethyl Cadmium
Dimethyl Cadmium

From the drawing above (Image courtesy of SAFC Global), the yellow atom is a Cadmium atom single-bonded to two other molecules. Each molecule is a methyl compound. A methyl compound is highly reactive and is formed of a central carbon atom (grey) and three hydrogen (white) atoms. This particular nasty is referred to as a methyl organometallic compound.

Methyl organmetallics are where you start looking for the most choking vapors, brighest flames, and fondest collection of curse words to ever come out of a chemistry lab. Methyl organometallics are small, highly reactive, and ready to start a party! Dimethyl cadmium is the little demon wedged in this fun collection of man-made nasties.

Spill the stuff and it’ll spread into a nice, wide, pool over your lab – and, of course, it will ignite on it’s own. I cant think of much that would ignite at room temperature but there you go.

What happens once you’ve got a warm fire going in your lab? We all then get to sniff some poisonous cadmium oxide smoke. It’s toxic to your lungs, liver and kidneys. Only a few micrograms per cubic meter are needed and that vapour gets absorbed really well into your blood stream. Cadmium compounds are carcinogenic – so assuming you survive all that chances are you’ll pick up a tumour somewhere down the road.

If that doesn’t happen – I’ll wager you’ll still regret you opened the bottle.

Lucifer’s partycracker

It can react with oxygen to form a thick crust of dimethyl cadmium peroxide – a friction sensitive explosive. This means that if you try and move it it blows up. I still don’t know exactly how you clean that up without blowing yourself up.

Some kids playing with dimethyl cadmium
Image credit :http://static2.businessinsider.com/image/50d0cac869bedd800e000034-480/party-fire-devil-dancing-club.jpg

Any attempt to clean up the explosive will either a) blow you up or b) distribute the rest of your delicious dimethyl cadmium into a fine mist. Inhaling it will give you some nasty surprises. Don’t use water either – just remember that science lesson you had about throwing sodium into water. Something similarly fun may happen.

So in summary this chemical is no longer popular (gee  whiz – I wonder why?) with chemists. It is still used in exotic areas of chemistry in developing “exciting” photosensitive and semiconducting materials (Again, not the kind of job you want).

So no, no one loves this chemical – which is why you’ve never heard of it. Play with it in your own time but keep it out of my ‘hood*.

*Pun of the word ‘neighbourhood’ and ‘fume hood’ 😉

It’s love actually!

Ever wonder whether love is something you control – or is it just your hormones and biases behind it?

What about chemistry – are you in control or is dopamine?

Well there’s actually 2 reasons why we all fall in love – a lot comes down to our need to reproduce.

Image Credit: http://sycofx.wordpress.com/2011/08/16/happiness-and-the-amygdala/

1. Sex drive – for blokes that’s coming from two structures in your brain. Your amygdala and your hypothalamus. Those brain structures evolved to get you to even look at partners.

2. Romantic love – this developed later and gave us a reason to focus our energy on just one person. The attachment and feeling of security evolved to help people stay together long enough to raise kids.

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Yucky, graphical Sumerian love.
Image credit: Terracotta plaque from Babylon. (Vorderasiatische Museum Berlin 3576 13.5×7.5 cm) Image credit: Assante 2002: Fig.1

The most important thing to note is that romantic love was not invented by Shakespeare, poets or even Hollywood. Love poetry was found in ancient Sumer (modern day Iraq) as long as 4,000 years ago. There’s also evidence of romantic love in over 150 different tribes and societies over the course of human history.

We’re all alike in the same basic and beautiful way – our amygdala and hypothalamus gives us a reason to look for love and our need to reproduce gives us the reason to keep on loving.

So, how much control do you think you have?