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I'm looking for a story I read in the 90s (probably written much earlier) about a man who is part of some sort of scientific group that discovers a way to build a doomsday weapon capable of cutting the planet in half. All it requires is a coil of wire and some commonly available chemicals.
The man discusses the matter with his wife, and they decide that
no one can be trusted with such dangerous information, so at their next meeting he murders everyone in the group by leaving a drop of acid to slowly burn into a cylinder full of nerve gas.
In the end,
his wife poisons him because she believes that not even her husband can be trusted not to someday use his knowledge to destroy the Earth.