What the heck is XV?
Nothing that was covered in my NBC classes. I'm assuming it came from a clueless fiction author with no personal experince in the gas chamber.
XV may be a copy typo for VX, a very deadly and very difficult to handle binary nerve agent.
Dyslexia is a horrible disease. I would assume the reporter meant ‘VX’... In which case, it is an organophosphate originally invented as a pesticide called ‘Amiton’. It was very effective, but found to be extremely toxic to people and was withdrawn in the 1950’s.
That’s when the British weapons researchers found it, boosted its potency and designated it as a class of agents known as ‘V’.
The most potent version was designated ‘VX’. The rest... Is history.
Not a substance to play with. But the two precursor chemicals are benign. Mix them... You’re toast.
It effectively causes convulsions followed by complete paralysis. Killing the victim in a long (minutes) drawn out and agonizing process: After most of your bones are broken, you stop breathing and your heart stops... But you’re still alive for another 3 minutes or so. Hopefully unconcious.