Breaking Bad : Season 1 : Episode 6: “Crazy Handful of Nothin'”
With Jesse unable to sell enough crystal to meet Walt’s mounting chemotherapy bills, Walt decides that it’s time to go wholesale. The distributor that took over Krazy-8’s patch is not very impressed by Jesse’s pitch, and Walt is thus forced to take a big step into the criminal underworld. In this post, I’ll be talking about mercury fulminate and the chemistry of explosions.
Before we get started, it’s interesting to note that Hank is quite familiar with the array of glassware and equipment in Walt’s storeroom. When he picks up the 5-litre round-bottomed flask, we can see that it’s actually a flat-bottomed flask – so either Walt misspoke when he showed it to Jesse back in episode one, or he had one of each type. Round- and flat-bottomed flasks look the same, but (as the name implies) flat-bottomed flasks have a flat base so they can stand on a level surface (round-bottomed flasks usually stand in cork rings or heater-stirrers, or are held with clamps).
In the classroom, Walt is giving a lecture about reaction rates and explosions. While some reactions proceed slowly and gradually (Walt’s example is rust build-up on a car), others are extremely fast – such as, hint hint, explosions. We can think of an explosion as a combustion reaction (the oxidation of a material in air) that happens almost instantaneously. Instead of heat and gases being produced slowly over the course of a few hours, they are produced all at once.
Low explosives such as gunpowder explode via deflagration. This is a technical term for combustion where the gas expands below the speed of sound (343 m s-1), such as petrol (gasoline) in an internal combustion engine. High explosives such as TNT explode via detonation. While this term is commonly used to mean any kind of explosion, it technically refers to combustion where the gas expands faster than the speed of sound, creating a destructive shock wave.
On the left-hand side of the blackboard, we can see:
2NO2 → 2NO + O2
Which is a typical decomposition reaction. On a fundamental level, two molecules of NO2 decompose to give two molecules of NO and one molecule of O2 – or, two molecules are decomposing to give three. Under normal conditions, all these molecules are gases, so if we decomposed NO2 in a confined space (such as a sealed container) the pressure would increase (by around 50 %, as one mole of any gas occupies the same volume as one mole of any other).
Walt has already set up the chemistry behind the episode’s pyrotechnic finale on the right-hand side of the blackboard, where we can see:
Hg(OCN)2 → Hg + 2CO + N2
Which tells us that mercury fulminate, Hg(OCN)2, decomposes to mercury, carbon monoxide and nitrogen. It does so extremely rapidly (its detonation velocity is around 4250 m s-1), and has been used for many years as a primary explosive (a sensitive explosive used to set off a larger charge) as it is quite unstable and liable to go off at any time. Appropriately, the word “fulminate” comes from the Latin fulmināre, which means “to strike with lightning”.
At first glance, Walt’s employment of mercury fulminate (he later refers to it as “fulminated mercury”) seems to be a little unrealistic. He presents Tuco with huge crystals, and if he was that good a crystalliser he’d have won a Nobel Prize all by himself. Previous attempts at crystallising mercury fulminate (the ones that didn’t end in explosions) have only yielded crystals less than 1 mm in length, and it wasn’t until 2007 that crystallographers succeeded in getting a definitive structure. In addition, as I’ve already mentioned, the stuff is incredibly sensitive to shock and friction. Both Tuco’s minders and Walt handle the bag quite roughly, and even if it made it to Tuco’s desk intact the explosion that Walt causes would certainly have set it off.
My best guess, artistic license aside, is that Walt encased safe amounts of mercury fulminate in some kind of crystal to give the appearance of meth whilst retaining some explosive power.
Elements in the credits
|Steven Michael QUezada||Uranium|
|Robb Wilson King||Tungsten|