|Aluminium is already highly prized. It's conductive, has a low melting
point, is very strong when alloyed, is impervious to rust and, above
all, it's extremely light.
But what if you could get it lighter - so light that it could float on
water. According to a model created by researchers at Utah State
University and Southern Federal University in Rostov-on Don, Russia,
such a thing is actually possible. The team used computational design to
conceive a form of crystalline aluminium with extremely low density.
They started with a known crystal lattice, in this case a diamond, and
substituted every carbon atom with an aluminium tetrahedron. The
resulting crystalline aluminium, called supertetrahedral aluminium, has
a density of just 0.61 grams per cubic centimetre, compared to the
density of normal aluminium, which is 2.7 grams per cubic centimetre.
Steel, by comparison, has a density of 7.75g/ccm. This means that a lump
of the semimetal would float on water, which has a density of 1g/ccm.