Strange spaghetti crystals shrink when hot and wet

Most materials expand when they absorb water or are exposed to heat, but some with a strange crystal structure do the opposite. Now it seems this counterintuitive behaviour is due to the formation of a tangled spaghetti structure within the crystal, a property that could lead to new anti-humidity building materials.

Zirconium tungstate, a metal oxide, shrinks by around ten per cent when water is added or it is heated to very high temperatures. “It a remarkable material. It acts like a reverse sponge,” says Andrew Goodwin of the University…