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.^[1]

Structure and properties

Structure and properties
Index of refraction, n_D	1.000444^[2]
Dielectric constant, ε_r	1.6761 ε₀ at −182 °C^[3] 1.0008181 ε₀ at −20 °C^[4]
Bond strength	?
Bond length	0.10870 nm ^[5]
Bond angle	109.5°
Magnetic susceptibility	−17.4×10⁻⁶ cm³/mol^[6]

Thermodynamic properties

Phase behavior
Triple point	90.67 K (−182.48 °C), 0.117 bar^[7]
Critical point	190.6 K (−82.6 °C), 46.0 bar^[7]
Std enthalpy change of fusion, Δ_fusH^o	1.1 kJ/mol
Std entropy change of fusion, Δ_fusS^o	12.1 J/(mol·K)
Std enthalpy change of vaporization, Δ_vapH^o	8.17 kJ/mol
Std entropy change of vaporization, Δ_vapS^o	? J/(mol·K)
Solid properties
Std enthalpy change of formation, Δ_fH^o_solid	? kJ/mol
Standard molar entropy, S^o_solid	? J/(mol K)
Heat capacity, c_p	? J/(mol K)
Liquid properties
Std enthalpy change of formation, Δ_fH^o_liquid	? kJ/mol
Standard molar entropy, S^o_liquid	? J/(mol K)
Heat capacity, c_p	? J/(mol K)
Gas properties
Std enthalpy change of formation, Δ_fH^o_gas	−74.6 kJ/mol^[8]
Standard molar entropy, S^o_gas	186.3 J/(mol K)^[8]
Enthalpy of combustion Δ_cH^o	−802 kJ/mol^[9]
Heat capacity, c_p	35.7 J/(mol K)^[8]
van der Waals' constants^[10]	a = 228.29 L² kPa/mol² b = 0.04278 L/mol

Vapor pressure of liquid

P (mm Hg)		1	10	40	100	400	760	1520	3800	7600	15200	30400	45600
T (°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.

Methane vapor pressure vs. temperature. Uses formula $\log _{10}P_{\text{mm Hg}}=6.61184-{\frac {389.93}{266.00+T_{^{\circ }{\text{C}}}}}$ given in *Lange's Handbook of Chemistry*, 10th ed. Note that formula loses accuracy near T_crit = −82.6 °C

Spectral data

UV-Vis
λ_max	? nm
Extinction coefficient, ε	?
IR
Major absorption bands	3019, 2917, 1534, 1306 cm⁻¹^[11]
NMR
Proton NMR
Carbon-13 NMR	−2.3 ppm^[12]
Other NMR data
MS
Masses of main fragments

This box:

Except where noted otherwise, data relate to Standard temperature and pressure.
Reliability of data general note.

References

^ Material Safety Datasheet . Iowa State
^ Haynes, p. 10.256
^ Haynes, p. 6.212
^ Haynes, p. 6.221
^ Haynes, p. 9.45
^ Haynes, p. 3.578
^ ^a ^b Haynes, p. 6.175
^ ^a ^b ^c Haynes, p. 5.26
^ Haynes, p. 5.67
^ Lange's Handbook of Chemistry, 10th ed, pp. 1522–1524.
^ Haynes, p. 9.106
^ Haynes, p. 8.67

Cited sources

Haynes, William M., ed. (2016). CRC Handbook of Chemistry and Physics (97th ed.). CRC Press. ISBN 9781498754293.

[1] Material Safety Datasheet . Iowa State

[2] Haynes, p. 10.256

[3] Haynes, p. 6.212

[4] Haynes, p. 6.221

[5] Haynes, p. 9.45

[6] Haynes, p. 3.578

[crit-7] Haynes, p. 6.175

[thermo-8] Haynes, p. 5.26

[9] Haynes, p. 5.67

[lange1522-10] Lange's Handbook of Chemistry, 10th ed, pp. 1522–1524.

[11] Haynes, p. 9.106

[12] Haynes, p. 8.67

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