Here I summarize the solidifying pressure (liquid-solid transition) of common gases at room temperature (300 K).
These are the pressures where you start to see diffraction lines from gases loaded in pressure cells.
He 11.5 GPa¹
Ne 4.7 GPa²
Ar 1.3 GPa¹
Kr 0.83 GPa¹
Xe 0.42 GPa¹
summarized in Shimuzu et al Phys. Rev. B 71, 014108 (2005)
¹ Rare Gas Solids, edited by J. A. Venables and M. L. Klein (Academic, New York, 1976), Vols. I and II.
² Finger et al Appl. Phys. Lett. 39, 892 (1981)
H₂ 5.4 GPa 1
H₂O 1.3 GPa (ice VI)
2.3 GPa (ice VII) 2
CH₄ 1.7 GPa 3
N₂ 2.4 GPa 4
CO₂ 0.5 GPa 5
CO 2.5 GPa 6
O₂ 5.5 GPa 7
F₂ 2.4 GPa 8
Cl₂ 2.7 GPa 9
1 (this is the lowest Z material, diffraction pattern is difficult to collect), Ji et al Nature 573, 558–562 (2019)
2 Kamb and Davis, PNAS, 52 (6) 1433-1439 (1964) | Bezacie et al J. Chem. Phys. 141, 104505 (2014)
3 Hirai et al J. Phys.: Conf. Ser. 121 102001
4 Zinn et al J. Chem. Phys. 87 126 (1987)
5 Santoro and Gorelli, Chem. Soc. Rev. 35, 918-931 (2006)
6 Katz et al J. Phys. Chem. 88 (15), 3176-3179 (1984)
7 Schiferl et al Acta Cryst. B37, 1329-1332 (1981)
8 Schiferl et al J. Chern. Phys., Vol. 87, No.5, (1987)
9 Johannsen and Holzapfe J. Phys. C: Solid State Phys. 16 L1177 (1983)
Br2
HCl
HF
N2O