Water Properties (abbreviated list)

**List of physical data concerning liquid H₂O**
Property	Data
Area, surface covered	19.0 Å² mol^-1 (monolayer [795 ])
Atmospheric content	19.66 g kg^-1 (relative humidity = 100)
Boiling point	100.0°C, 373.1243 K see [88]
CAS registry number	7732-18-5
Compressibility, adiabatic (κ_S)	0.4477 GPa^-1 [620 ]
Compressibility, isothermal (κ_T)	0.4599 GPa^-1 [507]
Conductivity, electrolytic	0.05501 μS cm^-1 [737])
Conductivity, thermal	0.610 W m^-1 K^-1[IAPWS]
Critical point	647.096 K, 22.064 MPa, 322 kg m^-3 (IAPWS)
Cryoscopic constant	1.8597 K kg mol^-1
Density	997.05 kg m^-3 [67, 112]
Dielectric constant	78.4 [63]
Diffusion coefficient	0.2272 Å² ps^-1 [8],
Dipole moment, μ	2.95±0.2 D (liquid, 27°C) [129]
Ebullioscopic constant	0.5129 K kg mol^-1
Enthalpy of vaporization	40.657 kJ mol^-1 (100°C) [61]
Enthalpy of fusion	6.00678 kJ mol^-1 (0°C) [1385 ]
Expansion coefficient (α)	0.000253 °C^-1 [68]
Magnetic susceptibility	-1.64x10^-10 m³ mol^-1 [670 ]
Melting point	0.00°C, 273.152519 K (IAPWS)
Molality	55.508472 mol kg ^-1
Molar concentration	55.345 mol L^-1
Molar mass	18.015268 g mol^-1
pH	6.9996 (based on [112])
pK_a	15.7422 (based on [112])
pK_w	13.9991 [112]
Refractive index	1.33286 (λ = 589.26 nm) [310]
Resistance, electrical	18.18 MΩ cm [737 ]
Specific heat capacity, C_P	75.338 J mol^-1 K^-1 calculated from [1154 ]
Specific heat capacity, C_v	74.539 J mol^-1 K^-1 [67]
Speed of sound	1496.7 m s^-1 [620]
Surface tension	0.07198 J m^-2 [IAPWS]
Triple point	0.01°C, 611.657 Pa, 0.99978 g cm^-3 [536]
Vapor pressure	3.165 kPa [808]
Viscosity, dynamic	0.8909 mPa s [IAPWS]
Viscosity, kinematic	0.8935 x 10^-6 m² s^-1
Volume, molar	18.0685 cm³ [1006 ]

All the data is for liquid water at 25°C, 101.325 kPa unless clearly other conditions apply. For more details go to the extended list.