Methane (data page)

This page provides supplementary chemical data on methane.

Material Safety Data Sheet

The handling of this chemical may incur notable safety precautions. It is highly recommend that you seek the Material Safety Datasheet (MSDS) for this chemical from a reliable source such as SIRI, and follow its directions.

Structure and properties

Structure and properties
Index of refraction, nD	?
Dielectric constant, εr	1.7 ε0 at ? °C
Bond strength	?
Bond length	.117 nm
Bond angle	109.5
Magnetic susceptibility	?

Thermodynamic properties

Phase behavior
Triple point	90.67 K (−182.48 °C), 0.117 bar
Critical point	190.6 K (−82.6 °C), 46 bar
Std enthalpy change of fusion, ΔfusHo	1.1 kJ/mol
Std entropy change of fusion, ΔfusSo	? J/(mol·K)
Std enthalpy change of vaporization, ΔvapHo	8.17 kJ/mol
Std entropy change of vaporization, ΔvapSo	? J/(mol·K)
Solid properties
Std enthalpy change of formation, ΔfHosolid	? kJ/mol
Standard molar entropy, Sosolid	? J/(mol K)
Heat capacity, cp	? J/(mol K)
Liquid properties
Std enthalpy change of formation, ΔfHoliquid	? kJ/mol
Standard molar entropy, Soliquid	? J/(mol K)
Heat capacity, cp	? J/(mol K)
Gas properties
Std enthalpy change of formation, ΔfHogas	−74.87 kJ/mol
Standard molar entropy, Sogas	186.61 J/(mol K)
Enthalpy of combustion ΔcHo	–882.0 kJ/mol
Heat capacity, cp	35.69 J/(mol K)
van der Waals' constants[1]	a = 228.29 L2 kPa/mol2 b = 0.04278 liter per mole

Vapor pressure of liquid

P in mm Hg		1	10	40	100	400	760	1520	3800	7600	15200	30400	45600
T in °C		–205.9(s)	–195.5(s)	–187.7(s)	–181.4	–168.8	–161.5	–152.3	–138.3	–124.8	–108.5	–86.3	—

Table data obtained from CRC Handbook of Chemistry and Physics 44th ed. Annotation "(s)" indicates equilibrium temperature of vapor over solid. Otherwise temperature is equilibrium of vapor over liquid. Note that these are all negative temperature values.

log₁₀ of methane vapor pressure vs. temperature. Uses formula: $\scriptstyle \log_{10} P_{mmHg} = 6.61184 - \frac {389.93} {266.00 + T}$ given in Lange's Handbook of Chemistry, 10th ed. Note that formula loses accuracy near T_crit = −82.6°C

Spectral data

Methane infrared spectrum

UV-Vis
λmax	? nm
Extinction coefficient, ε	?
IR
Major absorption bands	~3020 cm−1
	~1300
NMR
Proton NMR
Carbon-13 NMR
Other NMR data
MS
Masses of main fragments

References

1. ^ Lange's Handbook of Chemistry, 10th ed, pp 1522-1524

Except where noted otherwise, data relate to standard ambient temperature and pressure.

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