Scientists have discovered new molecular properties of water opening research paths into water’s crucial roles in nature.
Water has some interesting properties that set it apart from other known liquids: it heats up and evaporates, condenses and liquifies, freezes and melts.
Although it is everywhere and we are made almost entirely of water, there are still some unknown questions about the miracle liquid.
Just recently, scientists managed to get to the bottom of the water-splitting process to give answers about how a water molecule dissociates into hydrogen and oxygen atoms.
Water serves as a solvent, and a medium for life, without which most chemical reactions wouldn’t take place.
But water’s unique physical and chemical properties don’t stop here.
A water molecule is a simple structure of three atoms, two of hydrogen and one of oxygen (H2O), two of the most abundant elements in the observable Universe.
Attracted to each other, water molecules create what chemists call “hydrogen bonds”, believed to hold the answer to the physical and chemical behavior of water.
It was long thought that water transports the two products of its own ionization, H+ and OH− ions, symmetrically in all directions. But digital simulations and models have shown the opposite, that it’s an asymmetrical process.
Researchers at New York University think this “asymmetry”, if controlled, “could be exploited in different applications by tailoring a system to favor one ion over the other”.
Water’s density varies according to ambient temperature and reaches its maximum at 4 °C (39 °F, and it’s called Temperature of Maximum Density (TMD).
Researchers cooled water down to its TMD and used special magnetic resonance instruments to track lifetimes of charged ions and “showed that the difference in lifetimes of the two ions reaches a maximum value (the greater the lifetime, the slower the transport). By accentuating the difference in lifetimes, the asymmetry became glaringly clear.”
To our senses, liquid water is always the same flowing substance, but on a molecular scale, water molecules are never the same as hydrogen atoms tend to jump from one molecule to another.
Researchers focused on the speed at which hydrogen atoms hop around, and “found that one of the geometrical arrangements of hydrogen bonds led to significantly slower hops for OH− than for H+ at four degrees Celsius…In addition, their results showed that molecules’ hopping behavior changed abruptly at this temperature.”
Now that this experiment has confirmed that water transports protons (H+) and hydroxide ions (OH−) in an asymmetrical way, harnessing this mechanism will pave the way to “new materials for clean energy applications”.