Both of its allotropic forms are metallic conductors. The discovery of a quasispherical allotropic molecule borospherene (B) was announced in July 2014. The physical properties of carbon vary widely with the allotropic form. The discovery of the quasispherical allotropic molecule borospherene (B) was announced in July 2014. These allotropic forms of silicon are not classified as crystalline silicon. Carbon is also known in several other allotropic forms, including semiconducting buckminsterfullerene (C). Multiple allotropic forms have been identified for lithium at high pressures. Sulfur, while usually polycrystalline, may also occur in other allotropic forms with completely different properties. Beta titanium alloys exhibit the BCC allotropic form of titanium (called beta).