Gas	Atomic wt., g/mol	Atomic radius, nm	Thermal conductivity, mW/m·K		Specific heat, kJ/kg·K	Density kg/m³	Crystal structure
Gas	Atomic wt., g/mol	Atomic radius, nm	300 K	600 K	Specific heat, kJ/kg·K	Density kg/m³	Crystal structure
H	1.008	46	186.6	309.1	14.304	0.089	HCP/cubic
He	4.003	176	155.7	251.6	5.193	0.166	HCP/cubic
Ar	39.95	174	17.7	30.3	0.52	1.66	FCC
Ne	20.18	160	49.4	78.5	1.03	0.839	FCC
Xe	131.29	12.4	5.5	10.3	0.158	5.898	FCC
N₂	14.01	71	26	41.8	1.040	1.165	Cubic/HCP