Scientists build a dodecahedron with 20 silicon atoms

The Si₂₀ dodecahedron is roughly as large as the C₆₀ molecule – or Buckyball – discovered in 1985. However, while the carbon atoms in C₆₀ form double bonds, the atoms in the silicon dodecahedron are connected through single bonds and this, says the team, means it is related to dodecahedrane (C₂₀H₂₀). "In its day, dodecahedrane was viewed as the 'Mount Everest' of organic chemistry because it initially could only be synthesised through a 23 step sequence. In contrast, our Si20 cage can be created in one step starting from Si2 building blocks," said Professor Matthias Wagner.

The Si₂₀ hollow bodies are always filled with a chloride ion. On its surface, the cluster carries eight Cl atoms and 12 Cl₃Si groups. In the future, the researchers are planning to use the surface bound Cl₃Si anchor groups to produce three dimensional nanonetworks out of Si₂₀ units.

According to Prof Wagner: "Spatially strictly limited silicon nanoparticles display fundamentally different properties to conventional silicon wafers." Access to siladodecahedrane is therefore said to open up the possibility of studying the fundamental electronic properties of cage like Si nanoparticles.