Hg is an electricity conductor, so when forced into a circular (toroidal) shape it behaves exactly like a coiling. It can generate magnetic field if an electrical charge runs through it, it can receive an induced magnetic field, generating electricity in its circuit (short-circuit, in fact).
Yes, anything changes under extreme pressure or temperature (low or high), but it has to be a ridiculously high pressure, probably only the surface of a neutron star could make Hg shrink its volume. As for temperature, the range is narrower, in some certain laboratory created conditions it can be brought to vapors (high temperature) … I do not know if it can be brought to its freezing point and turned from liquid to solid – probably yes.