US researchers have made the world’s smallest building blocks. The nanocubes are just one nanometer across.Stacked like bricks, they could make up a range of materials with useful properties such as light emission or electrical conduction.

Many chemists are currently trying to develop molecular-scale construction kits in which the individual components are single molecules to provide the polymers of the future. Conventional polymers are chainlike molecules. These entangle to form plastics ranging from soft polyethylene to hard polystyrene.

Chemists can exert some influence over the properties of the bulk plastic by altering the shape and composition of the molecular chains. But they have little control over how the chains weave together.

Richard Laine and colleagues at the University of Michigan in Ann Arbor want to replace chains with bricks. Their molecular units are silicon and oxygen atoms linked into a cube-shaped framework with a silicon at each corner.