And originally the Enterprise
in its energy reactors (whatever they were at that stage in the production). But it was quickly realized that using a real element
with known properties
was going to restrict story-telling potential. So they created dilithium, possessing any potential properties the writers might need in the future.
is a real thing, with known properties
. It couldn't be a hull material; better to invent hyponeutronium
with whatever properties the story might require (including being able to be made into hulls and doors).