Some properties of normal hydrogen and deuterium

normal hydrogen deuterium

Atomic hydrogen

atomic number 1 1

atomic weight 1.0080 2.0141

ionization potential 13.595 electron volts 13.600 electron volts

electron affinity 0.7542 electron volts 0.754 electron volts

nuclear spin 1/2 1

nuclear magnetic moment (nuclear magnetons) 2.7927 0.8574

nuclear quadrupole moment 0 2.77(10⁻²⁷) square centimetres

electronegativity (Pauling) 2.1 ~2.1

Molecular hydrogen

bond distance 0.7416 angstrom 0.7416 angstrom

dissociation energy (25 degrees C) 104.19 kilocalories per mole 105.97 kilocalories per mole

ionization potential 15.427 electron volts 15.457 electron volts

density of solid 0.08671 gram per cubic centimetre 0.1967 gram per cubic centimetre

melting point −259.20 degrees Celsius −254.43 degrees Celsius

heat of fusion 28 calories per mole 47 calories per mole

density of liquid 0.07099

(−252.78 degrees) 0.1630

(−249.75 degrees)

boiling point −252.77 degrees Celsius −249.49 degrees Celsius

heat of vaporization 216 calories per mole 293 calories per mole

critical temperature −240.0 degrees Celsius −243.8 degrees Celsius

critical pressure 13.0 atmospheres 16.4 atmospheres

critical density 0.0310 gram per cubic centimetre 0.0668 gram per cubic centimetre

heat of combustion to water (g) −57.796 kilocalories per mole −59.564 kilocalories per mole