basic chemical bonds

thingiverse

I study nanoscale thermal transport, and the chemistry kits you might buy never seem to come with enough of a given bond type to construct very many unit cells of a given crystal. So I started printing my own, and I use these as instructional models to teach my dogs about crystallography. Diamond has the highest thermal conductivity in existence. why? because the sp3 bonds are strong, stiff, and the center-cubic crystalline structure (left, in the photo) is also quite strong. This means vibrational waves (which carry heat!) can easily travel across the structure. Gallium Nitride is a semiconductor of great interest for its electronic structure *and* high thermal conductivity. GaN adheres to the Wurtzite structure (right, in the photo), which is very similar, with the same tetrahedral bonds, but arranged slightly differently (notice when two tetrahedra are joined, with overlapping central atoms, the pair of 3 outer atoms are either aligned (wurtzite), or not aligned (center cubic).