Ideal gas thermodynamic properties,C°p,S°,(G°−H°298)/T,H°t−H°298,&Dgr;H°F,&Dgr;G°Fand logKpof formation for CH3, CD3, CD4, C2D2, C2D4, C2D6, C2H6, CH3N2CH3and CD3N2CD3in the temperature range O–3000 K and at 1 atmosphere have calculated by statistical thermodynamic methods employing spectroscopic and other molecular constants. The rigid rotor‐harmonic oscillator model has been used. Estimated uncertainties in the thermodynamic properties due to uncertainties in the molecular properties and estimates of the effects of vibrational anharmonicities are also reported for each compound at three temperatures.