title: Methane (data page)
text: # 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.
  
  ## Structure and properties
  
  Structure and properties :
  
  | Index of refraction, $n_D$ | 1.000444 |
  | - | - |
  | Dielectric constant, $ε_r$ | 1.6761 $ε_0$ at −182 °C 1.0008181 $ε_0$ at −20 °C |
  | Bond strength | ? |
  | Bond length | 0.10870 nm |
  | Bond angle | 109.5° |
  | Magnetic susceptibility | $−17.4×10^{−6}$ $cm^3/mol$ |
  
  ## Thermodynamic properties
  
  Phase behavior :
  
  | Triple point | 90.67 K (−182.48 °C), 0.117 bar |
  | - | - |
  | Critical point | 190.6 K (−82.6 °C), 46.0 bar |
  | Std enthalpy change of fusion, $Δ_{fus}H^o$ | 1.1 kJ/mol |
  | Std entropy change of fusion, $Δ_{fus}S^o$ | 12.1 J/(mol·K) |
  | Std enthalpy change of vaporization, $Δ_{vap}H^o$ | 8.17 kJ/mol |
  | Std entropy change of vaporization, $Δ_{vap}S^o$ | ? 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 |
  | Standard molar entropy, $S^o_{gas}$ | 186.3 J/(mol K) |
  | Enthalpy of combustion $Δ_cH^o$ | −891 kJ/mol |
  | Heat capacity, $c_p$ | 35.7 J/(mol K) |
  | van der Waals' constants | a = 228.29 $L^2$ $kPa/mol^2$ b = 0.04278 L/mol |
  
  ## Vapor pressure of liquid
  
  | P (mm Hg) | P (mm Hg) | 1 | 10 | 40 | 100 | 400 | 760 | 1520 | 3800 | 7600 | 15200 | 30400 | 45600 |
  | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
  | T (°C) | 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.
  
  ## Spectral data
  
  UV-Vis :
  
  | $λ_{max}$ | ? nm |
  | - | - |
  | Extinction coefficient, ε | ? |
  | IR ||
  | Major absorption bands | 3019, 2917, 1534, 1306 $cm^{−1}$ |
  | NMR ||
  | Proton NMR | |
  | Carbon-13 NMR | −2.3 ppm |
  | Other NMR data | |
  | MS ||
  | Masses of main fragments | |
  
  * view
  * Except where noted otherwise, data relate to Standard temperature and pressure.
  * Reliability of data general note.
  