Basically, I want to know if molecular hydrogen (H$_2$) can form hydrogen bonds with other molecules (CH$_4$, CO$_2$, N$_2$). I'm trying to model the mixture of these molecules with SAFT equations of state, and I want to know if I'll have to add the effects of associating fluids (capable of forming H-bonds).
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1$\begingroup$ I could imagine that in a solid or dense fluid with a very particular structure, H-atoms in some hydrogen molecules might be so disposed that one was negatively polarized (closer to a hydride) and the other positively (closer to a proton) setting up conditions for H-bonding. I've never heard of this happening though. $\endgroup$– Buck Thorn ♦Commented Mar 8, 2023 at 6:58
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5$\begingroup$ Molecules that do hydrogen bonding are always fairly polar. Dihydrogen is not polar. So, no, whatever interactions are happening will not be hydrogen bonds. $\endgroup$– matt_blackCommented Mar 8, 2023 at 9:58
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1$\begingroup$ @matt_black nonpolar molecules can form hydrogen bonds. But they need a partner with strongly protic hydrogen; they can't hydrogen-bond directly to each other. $\endgroup$– Oscar LanziCommented Mar 8, 2023 at 18:50
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$\begingroup$ I suspect not under normal conditions but maybe under ultra high pressure where solid hydrogen can be formed a hydrogen bond is very much possible. $\endgroup$– VolpinaCommented Mar 8, 2023 at 21:18
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$\begingroup$ @OscarLanzi Examples under non-extreme conditions? And would we normally classify any as "hydrogen bonds"? $\endgroup$– matt_blackCommented Mar 9, 2023 at 0:51
2 Answers
Something like hydrogen bonding with $\ce{H2}$ molecules appears to occur in hydrogen ion clusters. Clampitt and Gowland[1] study these clusters in connection with stellar nebulae and report that the $\ce{H_{15}^+}$ ion is especially stable; this likely has a $\ce{H3^+}$ core (which acts as the protic hydrogen) surrounded by six associated $\ce{H2}$ molecules.
Other nonpolar molecules, with lower ionization energies and greater polarizability, may form weak hydrogen bonds in more ordinary chemical environments. Such an interaction between methane and water, which may occur in methane clathrate-hydrates, is reported by Isaev[2].
All such hydrogen-bonding interactions with nonpolar molecules require a strongly protic hydrogen source with which the electrons of the nonpolar molecules can overlap. A simple mixture of low-polarity, nonprotic gases would not of itself generate any hydrogen bonding.
CLAMPITT, R., GOWLAND, L. (1969) "Clustering of Cold Hydrogen Gas on Protons". Nature 223, 815–816. https://doi.org/10.1038/223815a0
Isaev, A.N. (2016) "O–H···C hydrogen bond in the methane–water complex". Russ. J. Phys. Chem. 90, 1978–1985. https://doi.org/10.1134/S0036024416100150
By definition, no, they can't. According to IUPAC's definition of a hydrogen bond:$^1$
The hydrogen bond is an attractive interaction between a hydrogen atom from a molecule or a molecular fragment X–H in which X is more electronegative than H, and an atom or a group of atoms in the same or a different molecule, in which there is evidence of bond formation.
That isn't to say that you could not get dispersion interactions forming due to the instantaneous changes in electron distributions, but they will probably be negligible. There is also the possibility of other types of non covalent bonding (e.g. halogen [F, Cl, Br,...], chalcogen [O, S, Se,...], pnicogen [N, P, As,...], tetrel [C, Si,...], etc. bonding),$^2$ but be careful when you use the term 'hydrogen bond'.
Arunan, E.; Desiraju, G. R.; Klein, R. A.; Sadlej, J.; Scheiner, S.; Alkorta, I.; Clary, D. C.; Crabtree, R. H.; Dannenberg, J. J.; Hobza, P.; et al. Definition of the hydrogen bond (IUPAC Recommendations 2011). Pure Appl. Chem. 2011, 83 (8), 1637-1641. DOI: 10.1351/PAC-REC-10-01-02
Alkorta, I.; Elguero, J.; Frontera, A. Not Only Hydrogen Bonds: Other Noncovalent Interactions. Crystals 2020, 10 (3), 180. DOI: 10.3390/cryst10030180.