Thermal Conductivity of Elements with Complex Lattices: B, P, S

The thermal conductivities of β-rhombohedral boron, orthorhombic (black) phosphorus, and orthorhombic sulfur have been measured down to 3^∘{}K. These results, as well as some from the literature on cubic (white) phosphorus and on boron carbide, have been interpreted by comparing them with the thermal-conductivity-versus-temperature curves expected for simple models of molecular solids and of monatomic solids. Sulfur and white phosphorus behave like simple molecular solids, and black phosphorus behaves like a monatomic solid, while the behavior of boron and boron carbide, whose lattices are composed of B₁₂ icosahedra, lies between these two limits.