Scientists have discovered a new state of water

2024 Author: Seth Attwood | [email protected]. Last modified: 2023-12-16 15:55

One of the basic things we learn in science classes at school is that water can exist in three different states: solid ice, liquid water, or gaseous vapor. But recently, an international team of scientists have found signs that liquid water can actually exist in two different states.

While conducting research work - the results were later published in the International Journal of Nanotechnology - scientists unexpectedly discovered that a number of properties change in water with a temperature of 50 to 60 ℃. This sign of the possible existence of a second liquid state of water has sparked a heated debate in scientific circles. If confirmed, then the discovery will find applications in many areas, including nanotechnology and biology.

Aggregate states, which are also called "phases", are the key concept of the theory of systems of atoms and molecules. Roughly speaking, a system consisting of many molecules can be organized in the form of a certain number of configurations depending on its total amount of energy. At high temperatures (and therefore at a higher energy level), a greater number of configurations are available to molecules, that is, they are less rigidly organized and move relatively freely (gas phase). At lower temperatures, molecules have fewer configurations and are in a more organized (liquid) phase. If the temperature drops even lower, they will assume one definite configuration and form a solid.

This is the general state of affairs for relatively simple molecules such as carbon dioxide or methane, which have three distinct states (liquid, solid, and gas). But more complex molecules have a larger number of possible configurations, which means that the number of phases increases. An excellent illustration of this is the dual behavior of liquid crystals, which are formed from complexes of organic molecules and can flow like liquids, but still retain a solid crystalline structure.

Since the phases of a substance are determined by its molecular configuration, many physical properties change dramatically when a substance passes from one state to another. In the aforementioned study, the scientists measured several control properties of water between 0 and 100 ℃ under normal atmospheric conditions (so that the water is liquid). Unexpectedly, they found dramatic variations in properties such as the surface tension of water and the refractive index (the index that reflects how light travels through water) at a temperature of about 50 ℃.

Special structure

How is this possible? The structure of the water molecule, H₂O, is very interesting and can be depicted as a kind of arrow, where the oxygen atom is located at the top, and two hydrogen atoms "accompany" it from the flanks. Electrons in molecules tend to be distributed asymmetrically, which is why the molecule receives a negative charge from the oxygen side compared to the hydrogen side. This simple structural feature leads to the fact that water molecules begin to interact with each other in a certain way, their opposite charges attract, forming a so-called hydrogen bond.

This allows water in many cases to behave differently from what other simple liquids have observed. For example, unlike most other substances, a certain mass of water takes up more space in a solid state (in the form of ice) than in a liquid state, due to the fact that its molecules form a specific regular structure. Another example is the surface tension of liquid water, which is twice that of other non-polar, simpler liquids.

The water is pretty simple, but not overwhelming. This means that the only explanation for the additional phase of water that has manifested itself is that it behaves a little like a liquid crystal. Hydrogen bonds between molecules maintain a certain order at low temperatures, but they can also come to another, more free state with increasing temperature. This explains the significant deviations observed by scientists during research.

If this is confirmed, the authors' conclusions may have many uses. For example, if changes in the environment (say, temperature) entail changes in the physical properties of a substance, theoretically this can be used to create sounding equipment. Or you can approach it more fundamentally - biological systems are composed mainly of water. How organic molecules (such as proteins) interact with each other is likely to depend on how the water molecules form the liquid phase. If you understand how water molecules behave on average at different temperatures, you can clarify how they interact in biological systems.

This discovery is a great opportunity for theorists and experimenters, as well as a great example of the fact that even the most familiar substance can hide secrets within itself.

Rodrigo Ledesma Aguilar