Table 1. Selected Physical and Chemical Properties of H₂O and D₂O⁸⁻¹¹.

property	H2O	D2O
molecular weight (g/mol)	18.02	20.03
melting point (°C)	0	3.82
boiling point (°C)	100	101.4
molar density (mol/L, 25.0 °C, 1 atm)	55.35	55.14
molecular polarizability (Å3)	1.45	1.26
viscosity (25 °C)	0.891	1.095
pH/pD (25 °C)	6.9976	7.43
dielectric constant (25 °C)	78.37	78.06