Color: colorless
State at 25°C: gas
Density (g/cm3): 0.0012
Hardness (Mohs): No data 
Melting Point (K): 63.34
Boiling Point (K): 77.4
Heat of Fusion (kJ/mol): 0.7
Heat of Vaporization (kJ/mol): 6
Heat of Atomization (kJ/mol): 473
Therm. Conductivity (J/m sec K): 0.03
Elec. Conductivity (1/mohm cm): 0
Abundance, Solar System: 6.496
Abundance, Earth's Crust: 1.3
Pure Cost ($/100g): $ 0.40
Bulk Cost ($/100g):  
Source: Air