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Dihydrogen bond: Difference between revisions
image and mention H---H distances
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In [[chemistry]], a '''dihydrogen bond''' is a kind of [[hydrogen bond]], an interaction between a [[metal hydride]] bond and an OH or NH group or
An early example of this phenomenon is credited to Brown and Heseltine.<ref>{{Cite journal
| issue = 23
| pages = 1551–1552
| date = 1996-01-01
| pmid = 19904922
}}</ref> In other words, the amine is a protic acid and the borane end is hydridic. The resulting B−H<sup>...</sup>H−N attractions stabilize the molecule as a solid. In contrast, the related substance [[ethane]], H<sub>3</sub>CCH<sub>3</sub>, is a gas with a boiling point 285 °C lower. Because two hydrogen
[[File:DihydrogenBondingBH4-H2O.png|thumb|Dihydrogen bonding is evident in the close H---H contacts between water of crystallization and the borohydride anion in the salt NaBH<sub>4</sub>(H<sub>2</sub>O)<sub>2</sub>.<ref name=ChemRev/>]]
Formation of a dihydrogen bond is assumed to precede formation of H<sub>2</sub> from the reaction of a hydride and a protic acid. A very short dihydrogen bond is observed in NaBH<sub>4</sub>·2H<sub>2</sub>O with H−H contacts of 1.79, 1.86, and 1.94 Å.<ref name=ChemRev>{{Cite journal
| doi = 10.1021/cr000021b
| volume = 101
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