It's not actually a gas; it's quite a thick, heavy oil.
It was developed in the 1950s during some pesticide research, actually,
and they found some agents which were particularly toxic.
I believe that nerve agents are some of the most dreadful chemicals
that chemists have ever synthesized.
The "V" stands for "venomous agent"
so this is venomous agent "X",
and there was a venomous agent "G"
and various other ones.
Perhaps it was the 22nd, 23rd one, wherever "X" is in the alphabet, that they made
or perhaps it just sounded sinister.
Fortunately, there is an organization based in the Hague,
the Organization for Prohibition of Chemical Weapons,
which over the last 20 or so years has succeeded
in getting 95% of all the stocks of chemical weapons in the world
to be destroyed.
I've got a model here of the VX agent.
It's got a number of atoms, as you can see.
This is a phosphorus-based reagent, as a lot of these nerve agents are.
So here we have a phosphorus,
we've got a double bond to an oxygen.
We've got an ethanol group here.
The interesting group is this here, and this is derived from taurine.
This is a sulfur, and in taurine that has more oxygens on it.
In this case, though, it doesn't.
And this phosphorus-to-sulfur bond here is a very weak bond
and that is the key part of this molecule which reacts
when it meets your nervous system.
I think that this chemical is obviously terribly dangerous
even to store, because if it gets out accidentally it could cause
enormous damage, kill thousands or perhaps more people,
depending how it's distributed.
So these are all called nerve agents
and that's because they interrupt your nervous system.
So the normal neurotransmitter
which is used in your nervous system
is this here; this is acetylcholine.
So the nerves work by sending an electrical signal from your brain to your muscles
and, when they get to the muscles, there's a junction.
The electrical message gets converted into a different type of message.
A neurotransmitter, or many many thousands of neurotransmitters, are released
and they drift across the synaptic gap to the muscle
and they accumulate in receptors
and the more accumulation is, the more of the stimulus for that particular muscle is.
So your lungs, for example, are constantly being told to breathe in, breathe out.
Your heart is constantly being told to beat and pump blood around you
and when you want to move your hand, your brain is telling
the muscles here to contract or release.
This neurotransmitter, acetylcholine, is responsible for much of that.
There are other neurotransmitters too, but this is the key one for that process.
So this, when it gets released, it soaks up into all the receptors
but of course at some point you want to release your hand
or your heart wants to beat the other way
and so these go in and out of these receptors
and then there's another molecule called acetylcholinesterase
which just comes along and chomps them up.
I call it the Pac-Man molecule because you can imagine
something coming along
and then it literally breaks this bond here
to make acetic acid—vinegar—and choline,
and the choline gets recycled back in the cell
and recreate more of the neurotransmitter.
This is going on thousands of times a second, so a very fast process.
So how does VX work?
Well, it works by mimicking this molecule here.
So this molecule is the natural "food", if you want, for Pac-Man.
This molecule comes in, and this again is a very weak bond and so it
comes off, and this gets attached to the Pac-Man molecule.
So the normal process would be
that the residue would come in and attack the carbon
of the acetylcholine
to make this carbon-oxygen bond, and then water can come in
and pluck that off again
and that happens many times a second
so this is always around to eat more
like a pair of scissors snipping all the acetate groups off.
When we have the phosphorus-oxygen bond, though, it's on there for good.
It's not coming off, unless you administer an antidote.
So what happens is, now that your acetylcholine in your synaptic gap in the nervous—
in that junction, if you like, between the muscle and the nerve,
that's not being eaten up, so it's always there
so it's always going into receptors to tell your muscle to contract.
And, of course, if it's your heart or if it's your lungs,
well, that's very quickly going to really mess up your normal breathing and living
indeed, most people who have this type of poisoning,
they die of asphyxiation because their lungs have stopped working correctly.
And of course all your peripheral muscles are being told by the same substance
what to do, so you will get uncontrolled movement, convulsions.
So really not very pleasant at all.
The other very common one, nerve agent, which people have used
or heard of, at least, hopefully not used, is sarin.
So VX is actually far more potent than even sarin.
It's extremely potent, so around about 10 milligrams,
that's a hundredth of a gram, really not very much
Really not very much,
is enough to kill an average human.
It has to be admitted that this video is the first opportunity
that I've had of wearing this tie
that was sent to me by a fan
anonymously—I don't know which fan,
about chemical weapons.
This is not the sort of tie that one can wear at a party.
People are not going to enjoy themselves when they see
vomiting, diarrhea, and the likes written on my tie,
but today it's really quite useful and appropriate
and I thank that fan, whoever he or she was, for sending it to me.
This initially reacts with the phosphorus, the sulfur,
to make this bond here, and then this group migrates down here
and that happens in a fairly rapid process
so the idea was to have elemental sulfur, which is just a nice yellow powder
and this other substance QL and within the actual missile
it's what were called binary missiles, or binary bombs
the chemical reaction would occur to make the very nasty nerve agent
and that of course made the bomb much easier to assemble.