Thermal conductivity for gas

Thermal conductivity of a substance is an intensive property that indicates its ability to conduct heat.

Air and other gases are generally good insulators, in the absence of convection. Light gases, such as hydrogen and helium typically have high thermal conductivity. Dense gases such as xenon have low thermal conductivity. An exception, sulfur hexafluoride, a dense gas, has a relatively high thermal conductivity due to its high heat capacity. Argon, a gas denser than air, is often used in double paned windows to improve their insulation characteristics.

The sources are:

Symbol
$k_{gas}$
Unit
W/(m.K)
Formulae
$2.40073953{\cdot}{10}^{-2}+7.278410162{\cdot}{10}^{-5} \theta_{gas}-1.788037411{\cdot}{10}^{-7} {\theta_{gas}}^2-1.351703529{\cdot}{10}^{-9} {\theta_{gas}}^3-3.322412767{\cdot}{10}^{-11} {\theta_{gas}}^4$humid air @ 1 atm (Tsilingiris2007)
$1.5207{\cdot}{10}^{-11} {T_{gas}}^3-4.8574{\cdot}{10}^{-8} {T_{gas}}^2+1.0184{\cdot}{10}^{-4} T_{gas}-3.9333{\cdot}{10}^{-4}$air @ 1 bar (Dumas&Trancossi2009)
$\frac{2.334{\cdot}{10}^{-3} {T_{gas}}^{\frac{3}{2}}}{164.54+T_{gas}}$air @ 1 bar (UW/MHTL 8406, 1984)
$-2.276501{\cdot}{10}^{-3}+1.2598485{\cdot}{10}^{-4} T_{gas}-1.4815235{\cdot}{10}^{-7} {T_{gas}}^2+1.73550646{\cdot}{10}^{-10} {T_{gas}}^3-1.066657{\cdot}{10}^{-13} {T_{gas}}^4+2.47663035{\cdot}{10}^{-17} {T_{gas}}^5$dry air @ at 1 atm (Irvine&Liley1984)
$2.43e-2+6.63{\cdot}{10}^{-5} \theta_{gas}$N2 (Vermeer1983)
$1.17e-2+6.2{\cdot}{10}^{-5} \theta_{gas}$SF6 (Vermeer1983)
$\frac{1461860-18539.4T_{gas}+77.7891{T_{gas}}^2+0.0241059{T_{gas}}^3}{29661.7+505.67T_{gas}+{T_{gas}}^2}$SF6 (Assael2012)
$-7.302{\cdot}{10}^{-3}+8.075{\cdot}{10}^{-5} \left(\theta_{gas}+\theta_{abs}\right)$CO2 (linear interpolation)
$-2.991{\cdot}{10}^{-3}+7.836{\cdot}{10}^{-5} \left(\theta_{gas}+\theta_{abs}\right)$O2 (linear interpolation)
Related
$\theta_{abs}$
$\theta_{gas}$
Choices
GasFormula0°C15°C25°C50°C75°C100°C
Air78%N2+21%O2+minor0.024360.0254990.0262470.0277340.0295010.031224
N2N20.0240010.0251080.0258350.0273850.028990.030557
SF6SF60.0116270.0127010.0134120.0147480.0166480.018548
CO2CO20.0146750.0158440.0166430.0186850.0207690.022875
COCO0.024740.025790.0264780.0281630.0298040.031411
O2O20.024350.025550.026340.0285180.305240.32531
H2H20.172580.180050.184880.196780.209390.22142
NH3NH30.0229160.0240730.0249340.027390.0302410.033443
SO2SO20.0084340.0090920.009540.0106810.0118560.013031
HeHe0.14620.151690.155310.16420.17290.18141
ArAr0.0164830.0172450.0177460.0188370.0200150.021161
KrKr0.0086520.0090820.0093630.0100440.0107110.011357
XeXe0.0051070.0053650.0055350.00595790.00637480.0067862
NeNe0.0454120.0470260.0480840.0506730.0531880.055638