Properties of Heavy water

Heavy water is nothing but ordinary water with a greater average molecular weight. The hydrogen atoms in a molecule of heavy water are isotopes with nuclei containing a proton and a neutron and hence are twice as heavy as a typical hydrogen atom.

Definition of heavy water 

Heavy water, commonly known as deuterium water,  includes heavy hydrogen instead of ordinary hydrogen. 2H2O or D2O are other ways to write it. Deuterium differs from the hydrogen found in water, known as protium, in that each deuterium atom has a proton and a neutron. In contrast, most hydrogen atoms only possess a proton. Heavy water does exist in nature, albeit in far lesser amounts than ordinary water. Heavy water accounts for around one out of every twenty million water molecules.

Heavy water formula

Heavy water is a mixture of oxygen and deuterium, a heavier isotope of hydrogen symbolized by the letters ‘2H’ or ‘D.’ The D2O is the heavy water formula, commonly known as deuterium oxide.

Properties of heavy water

• Deuterium water has a molecular mass of 20.02 grams/mole.
• It has a density of 1.107 g/ml.
• Heavy water has a dipole moment of 1.87 D.
• It has a melting point of 3.82 degrees Celsius.

Physical Properties of Heavy Water

The physical properties of heavy water consist of:

• At standard temperature and pressure, heavy water appears to be colorless.
• It occurs as an odorless liquid at normal temperature.
• An ice cube produced of deuterium oxide will sink in regular water because its density is approximately 11% higher than H2O.
• When heavy water and ordinary water are combined, the result is a homogeneous mixture.

Chemical Properties of Heavy Water

The chemical properties of heavy water are as follows:

• Because of their differing atomic weights, hydrogen isotopes have varied chemical properties.
• Changes in the solvent properties of water caused by excessive levels of deuterium can have a negative impact on biological systems.
• When compared to heavy water, normal water dissociates to a greater extent.
• At any given temperature, the concentration of D+ ions in a D2O sample is typically less than that of H+ ions in an H2O sample.

Types of Heavy water

After understanding the properties of heavy water. Let’s learn about the types of Heavy water, which is divided into multiple parts: 

Semi-heavy water (HDO)

• One protium, one deuterium, and one oxygen atom make up this type of heavy water, with the formula HDO.
• Water molecules tend to swap hydrogen atoms with one another. This means that HDO can be found in both protium and deuterium-containing water samples.
• Fifty per cent semi-heavy water, 25% normal water, and 25% heavy water make up a water sample with an equal amount of protium and deuterium.
• There is a dynamic equilibrium between HDO, D2O, and H2O in this sample.

Heavy-oxygen water

• Heavy-oxygen water is defined as water that contains heavier isotopes of oxygen, such as 17O and 18O.
• Because it has a larger density than conventional water, it is classified as a type of heavy water.
• The synthesis of the 18F isotope of fluorine requires heavy-oxygen water containing the 18O isotope of oxygen. It’s also used in radiopharmaceuticals and radiotracers.

 Tritiated Water(T2O)

• It’s a radioactive kind of water made up of Tritium (abbreviated as T or 3H) rather than protium.
• Tritiated water, also known as super-heavy water, is denoted by the formula T2O  and can be used to calculate the total volume of water in a body.
• T2O has a molar mass of 22.03 grams per mole and a density of 1.85 grams per ml.

Heavy Water’s Applications

Deuterium oxide, as previously stated, is an essential component in heavy water chemical formula and its nuclear reactors, where it serves as a coolant and neutron moderator. The following are some other major uses for heavy water.

• For the production of Deuterium, heavy water is needed.
• Photosynthesis is used as a tracer to research the mechanism of respiration.
• D2O is utilized in NMR (nuclear magnetic resonance) spectroscopy, which examines the magnetic fields surrounding atom nuclei.
• It is used to create isotopologues of various chemical molecules.
• Heavy water is frequently used in IR (infrared) spectroscopy instead of conventional water.
• It can also be used to slow down the neutrons in a nuclear reactor as a moderator. It can slow down fast-moving neutrons, allowing them to interact with the 235U isotope rather than the 238U isotope.
• A blend of D2O and heavy-oxygen water is used to measure the metabolic rate of people and animals.
• When deuterium in heavy water absorbs a neutron, Tritium is produced. Tritium is the active element in controlled nuclear fusion reactions.

Preparation Techniques

The heavy water chemical formula is made by electrolysing alkali-containing water for a long time.

• Water with NaOH as an electrolyte.
• Steel vessel serves as the cathode.
• Nickel sheet with holes as an anode.
• By passing CO2 gas through the electrolysis, seven alkalies are neutralized. Heavy water is the remaining product. 

Deuterium oxide was first produced in 1932. It is utilized in pressurized heavy water reactors as a neutron moderator and coolant (PHWR). 

Disadvantages

• Heavy water has an exorbitant price tag.
• There are two mechanically sealed closures per fuel channel; therefore, leakage is a significant issue. Because total leak-tightness cannot be guaranteed, Canadian designs often focus on recovering a high percentage of major water leakages.
• Design, manufacturing, and maintenance must all meet a very high level.
• Compared to PWR and BWR, the power density is significantly lower (9.7 kw/liter); hence the reactor size is enormous.

Conclusion

Deuterium water is a heavier isotope of hydrogen symbolized by the letters ‘2H’ or ‘D’. Deuterium differs from the hydrogen found in water, known as protium, in that each deuterium atom has a proton and a neutron. Fifty per cent semi-heavy water, 25% normal water, and 25% heavy water make up a water sample. Heavy water contains heavier isotopes of oxygen, such as 17O and 18O. It has a larger density than conventional water, so it is classified as a type of heavy water.