What makes the molecule so unusual is its two hydrogen bonds, which are similar to those found in water.
Chemists know that although water is one of the most common substances found on the planet, it has unusual properties. For example, the solid form - ice - is lighter than the liquid form and floats. Water also boils at a much higher temperature than would be expected from its chemical structure.
The cause of these strange behaviors are weak hydrogen bonds that hold water molecules together.
The new atmospheric molecule has two hydrogen bonds, which allows it to form a six-sided ring structure. Hydrogen bonds are usually weaker than the normal bonds between atoms in a molecule, which are known as covalent bonds. In fact, covalent bonds are 20 times stronger than hydrogen bonds. But in this case, these two hydrogen bonds are strong enough to affect atmospheric chemistry, Francisco says.
Lester says the new molecule exhibits its own unusual properties.
"The reaction involving this molecule proceeds faster as you go to lower temperatures, which is the opposite of most chemical reactions," she says. "The rate of reaction also changes depending on the atmospheric pressure, and most reactions don't depend on external pressure. The molecule also exhibits unusual quantum properties."
Lester says the unusual properties prevented scientists from being able to model the reaction for so long.
"This is not how we explain chemistry to high school students," she says.
Francisco says that this discovery will be used in areas other than atmospheric chemistry.
"Here's a situation where we were studying this purely environmental problem, but, because the findings are so fundamental, it may have broader ramifications to biological systems that depend on hydrogen bonds," he says.
|Contact: Steve Tally|