All elements have atoms as their basic unit, and an atom contains three fundamental particles, which are negatively charged electrons, positively charged protons and neutrons of neutral particles. The number of protons and neutrons present in the nucleus is called the mass number of elements, and the number of protons is called the atomic number. The same elements whose atoms contain the same number of protons, but different numbers of neutrons, are called isotopes. As an example, we can take hydrogen, which has three isotopes. This is hydrogen with zero neutrons, deuterium containing one neutron, and tritium - it contains two neutrons. This article will focus on a hydrogen isotope called deuterium, also known as heavy hydrogen.
What is deuterium?
Deuterium is an isotope of hydrogen that differs from hydrogen in a single neutron. Usually, hydrogen has only one proton, and deuterium has one proton and one neutron. It is widely used in fission reactions.
Deuterium (the chemical symbol D or ²H) is a stable hydrogen isotope found in nature in extremely small quantities. A deuterium nucleus called a deuteron contains one proton and one neutron, while the much more common hydrogen nucleus contains only one proton and does not contain neutrons. Therefore, each deuterium atom has a mass that is approximately twice the mass of a regular hydrogen atom, and deuterium is also called heavy hydrogen. Water in which ordinary hydrogen atoms are replaced by deuterium atoms is called heavy water.
Main characteristics
The isotopic mass of deuterium is 2.014102 units. Deuterium has a stable half-life, since it is a stable isotope.
The excess energy of deuterium is 13 135.720 ± 0.001 keV. The binding energy for the deuterium nucleus is 2224.52 ± 0.20 keV. Deuterium combines with oxygen to form D2O (2H2O), also known as heavy water. Deuterium is not a radioactive isotope.
Deuterium is not harmful to health, but can be used to create nuclear weapons. Deuterium is not artificially produced, as it naturally occurs in large quantities in ocean water and can serve many generations of people. It is recovered from the ocean using a centrifugation process.
Heavy hydrogen
Heavy hydrogen is the name of any of the higher hydrogen isotopes such as deuterium and tritium. But more often it is used for deuterium. Its atomic mass is about 2, and its nucleus contains 1 proton and 1 neutron. Thus, its mass is two times the mass of normal hydrogen. The additional neutron in deuterium makes it heavier than normal hydrogen, so it is called heavy hydrogen.
Heavy hydrogen was discovered by Harold Urey in 1931 - this discovery was awarded the Nobel Prize in Chemistry in 1934. Yuri predicted the difference between the vapor pressure of molecular hydrogen (H2) and the corresponding molecule with one hydrogen atom replaced by deuterium (HD), and thus the possibility of separation of these substances by distillation of liquid hydrogen. Deuterium was detected in the remainder of the distillation of liquid hydrogen. It was prepared in its pure form G.N. Lewis using the electrolytic concentration method. When water is electrified, gaseous hydrogen forms, which contains a small amount of deuterium, so deuterium is concentrated in water. When the amount of water decreases to about one hundred thousandths of its original volume as a result of ongoing electrolysis, an almost pure deuterium oxide, known as heavy water, is provided. This method of preparing heavy water was used during World War II.
Etymology and chemical symbol
The name "deuterium" comes from the Greek word deuteros, which means "second." This indicates that with an atomic nucleus consisting of two particles, deuterium is the second isotope after ordinary (or light) hydrogen.
Deuterium is often denoted by the chemical symbol D. As an isotope of hydrogen with a mass number of 2, it is also represented as H. The formula of deuterium is 2H. The International Union of Pure and Applied Chemistry (IUPAC) allows the use of both D and H, although H. is preferred.
How to get deuterium from water?
The traditional method of concentrating deuterium in water uses isotopic exchange in gaseous hydrogen sulfide, although more advanced methods are currently being developed. Separation of various hydrogen isotopes can also be carried out using gas chromatography and cryogenic distillation, which use differences in physical properties to separate isotopes.
Deuterium water
Deuterium water, also known as heavy water, is like ordinary water. It is formed by a combination of deuterium and oxygen and is designated as 2H2O. Deuterium water is more viscous than ordinary. Heavy water is 10.6% denser than normal, so the ice of heavy water is sinking in ordinary water. For some animals, deuterium water is toxic, while others are able to survive in heavy water, but they will develop in it more slowly than in normal. Deuterium water is not radioactive. The human body contains about 5 grams of deuterium, and it is harmless. If heavy water enters the body in large quantities (for example, about 50% of the water in the body becomes heavy), this can lead to cell dysfunction, and ultimately to death.
Differences in heavy water:
- The freezing temperature is 3.82 ° C.
- The boiling point is 101.4 ° C.
- The density of heavy water is 1.1056 g / ml (normal water is 0.9982 g / ml).
- The pH of heavy water is 7.43 (ordinary water 6.9996).
- There is a slight difference in the taste and smell of plain and heavy water.
Use of deuterium
Scientists have developed many uses for deuterium and its compounds. For example, deuterium is a non-radioactive isotopic indicator for studying chemical reactions and metabolic pathways. In addition, it is useful for studying macromolecules using neutron scattering. Deuterated solvents (such as heavy water) are usually used in nuclear magnetic resonance spectroscopy (NMR), because these solvents do not affect the NMR spectra of the studied compounds. Deuterated compounds are also useful for femtosecond infrared spectroscopy. Deuterium is also the fuel for nuclear fusion reactions that can someday be used to produce electricity on an industrial scale.