Superconductor: with transition tempperature under special conditions
Superconducting properties are only achieved in these elements under certain conditions, such as high pressure or when the element is present as a thin film.
6CCarbonblack, metallic-looking (graphite); clear (diamond) 14SiSiliconcrystalline, reflective with bluish-tinged faces 15PPhosphoruswhite, red and violet are waxy, black is metallic-looking 26FeIronlustrous metallic with a grayish tinge 34SeSeleniumgrey metallic-looking, red, and vitreous black allotropes 52TeTelluriumsilvery lustrous gray (crystalline); brown-black powder (amorphous) 53IIodinelustrous metallic gray (solid); black/violet (liquid); violet (gas)