Solid hydrogen is the solid state of the element hydrogen, achieved by decreasing the temperature below hydrogen’s melting point.

Solid hydrogen is the solid state of the element hydrogen, achieved by decreasing the temperature below hydrogen’s melting point of 14.01 K (−259.14 °C; −434.45 °F). It was collected for the first time by James Dewar in 1899 and published with the title “Sur la solidification de l’hydrogène” (English: On the solidification of hydrogen) in the Annales de Chimie et de Physique, 7th series, vol. 18, Oct. 1899.[1][2] Solid hydrogen has a density of 0.086 g/cm3 making it one of the lowest-density solids.