"The new bonds had a strength of 45.8 kilocalories per mol (a unit of chemical bonding energy), greater than some covalent bonds."
Scientists have recently discovered a totally new type of chemical bond – and it's way stronger than it has any right to be.
The new type of bond shows that the divide between powerful covalent bonds, which bind molecules together, and weak hydrogen bonds, which form between molecules and can be broken by something as simple as stirring salt into a glass of water, isn't as clear as chemistry textbooks would suggest.
Think back to that high-school chemistry class, and you'll remember that there are different types of bonds that link atoms together into molecules and crystal structures.
Ionic bonds link metals and non-metals to form salts. Strong covalent bonds bind together molecules like carbon dioxide and water. Far weaker hydrogen bonds form because of an electrostatic type of attraction between hydrogen and a more negatively charged atom or molecule, for instance causing water molecules to attract one another and form droplets or crystalline ice.
Ionic, covalent, and hydrogen bonds are all relatively stable; they tend to last for extended periods of time and have effects are easily observable.
But researchers have long known that during a chemical reaction, as chemical bonds are forming or breaking, the story is more complicated and involves "intermediate states" that may exist for tiny fractions of a second and are more difficult to observe.
In the new study, the researchers managed to keep these intermediate states going for long enough to make a detailed examination. What they found was a hydrogen bond with the strength of a covalent bond, binding atoms together into something resembling a molecule.
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