Einsteinium(III) iodide
Einsteinium triiodide is an iodide of the synthetic actinide einsteinium which has the molecular formula EsI. This crystalline salt is an amber-coloured solid. It glows red in the dark due to einsteinium's intense radioactivity. It crystallises in the hexagonal crystal system in the space group "R" with the lattice parameters "a" = 753 pm and "c" = 2084.5 pm with six formula units per unit cell. Its crystal structure is isotypic with that of bismuth(III) iodide.