This page provides supplementary chemical data on isobutane.

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 , and follow its directions.

Structure and properties

Structure and properties
Index of refraction, nD?
Abbe number?
Dielectric constant, εr? ε0 at ? °C
Bond strength?
Bond length?
Bond angle?
Magnetic susceptibility?
Surface tension10.3 dyn/cm at 20°C P 300 kPa

Thermodynamic properties

Phase behavior
Triple point113.55K (–159.8 °C), 0.019483 Pa
Critical point408.7 K (134.4 °C), 3655 kPa
Std enthalpy change of fusion, ΔfusHo4.59 kJ/mol
Std entropy change of fusion, ΔfusSo39.92 J/(mol·K)
Std enthalpy change of vaporization, ΔvapHo21.3 kJ/mol
Std entropy change of vaporization, ΔvapSo81.46 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, Soliquid200.79 J/(mol K)
Heat capacity, cp129.70 J/(mol K) –253°C to –13°C
Gas properties
Std enthalpy change of formation, ΔfHogas–134.2 kJ/mol
Standard molar entropy, Sogas249.7 J/(mol K)
Enthalpy of combustion, ΔcHo–2869 kJ/mol
Heat capacity, cp95.21 J/(mol K) at 20°C
van der Waals' constantsa = 1304.1 L2 kPa/mol2 b = 0.1142 liter per mole

Vapor pressure of liquid

P in mm Hg11040100400760152038007600152003040045600
T in °C–109.2–86.4–68.4–54.1–27.1–11.77.539.068.899.5——

Table data obtained from CRC Handbook of Chemistry and Physics 44th ed.

Vapor pressure of iso-butane. From formula: log 10 ⁡ P m m H g = 6.74808 − 882.80 240.0 + T {\displaystyle \scriptstyle \log _{10}P_{mmHg}=6.74808-{\frac {882.80}{240.0+T}}} obtained from Lange's Handbook of Chemistry, 10th ed.

Spectral data

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