Europium is a chemical element in the periodic table. It is used in energy, medicine and electronics and is the most expensive representative of lanthanides. What are the properties and characteristics of europium?
Element 63
The chemical element europium was first discovered by the Englishman William Crookes in 1886. But its properties did not immediately become known. Repeatedly Crookes and other scientists saw only the spectral lines of an unknown substance. His discovery is attributed to the Frenchman Eugene Demars, who not only discovered the element, but also isolated it from the mineral, described and gave the name.
Europium is a metal with an atomic number of 63. It does not occur independently and is present in nature in rare-earth minerals, such as monazite and xenotime. The amount of the europium chemical element in the earth's crust is 1.2 * 10 -4 %. For industrial production, metal is mined from monazite, since its content in this mineral reaches 1%.
The largest deposits of europium are in Kenya. It is also found in the United States, Brazil, Australia, the Scandinavian countries, Russia, Kazakhstan, etc.
Main characteristics
The chemical element europium is a silver-white metal. Its atomic mass is 151.964 (1) g / mol. It is soft and easily susceptible to mechanical stress, but only in an inert atmosphere, as it is a fairly active substance.
The melting point of the metal is 826 degrees Celsius, europium boils at a temperature of 1529 degrees. It can become superconducting (acquires the ability to zero electrical resistance) at a pressure of 80 GPa and a temperature of -271.35 Celsius (1.8 K).
There are two natural isotopes of the element europium 153 and europium 151 with different neutron contents in the nucleus. The first is quite stable and a little more common in nature. The second isotope is unstable and has alpha decay. The period of the chemical element europium 151 is 5 × 10 18 years. In addition to these isotopes, there are 35 more artificial ones. The longest half-life is Eu 150 (half-life 36.9 years), and one of the fastest is Eu 152 m3 (half-life 164 nanoseconds).
Chemical properties
The chemical element europium is in the group of lanthanides, together with Lanthanum, Cerium, Gadolinium, Promethium and others. He is the lightest and most active of all his "classmates." Europium quickly reacts with air, oxidizing and becoming covered with a film. Because of this, it is usually stored in paraffin or kerosene in special containers and flasks.
Europium is also active in other reactions. In compounds, it is usually trivalent, but sometimes it is also divalent. When heated in an oxygen atmosphere, it forms the Eu 2 O 3 compound in the form of a white-pink powder. With a little heat, it easily reacts with nitrogen, hydrogen and halogens. Many of its compounds are white with light shades of orange and pink.
Europium (III) cations are obtained by decomposition of solutions of salts of sulfate, oxalate, nitrate. In industry, a metal is obtained using carbon or lanthanum by reducing its oxide or by electrolysis of its EuCl 3 alloy.
Of all lanthanides, only the emission spectrum of europium (III) ions can be perceptible to the human eye. When used to generate laser radiation, the color of its beam is orange.
Application
Europium found a chemical element in the field of electronics. In color television, it is used to activate red or blue phosphors. Its connection with silicon EuSi 2 forms thin films and is used for the manufacture of microcircuits.
The element is used for the production of fluorescent lamps and fluorescent glass. In medicine, some forms of cancer were treated with it. Its artificial isotope europium 152 serves as an indicator in chemical research , and the isotope number 155 is used for medical diagnostics.
It is stronger than other lanthanides to absorb thermal neutrons, which is very useful in nuclear energy. For these purposes, its oxide, a compound with boric acid (europium borate) and a binary compound with boron (europium hexaboride) are used. The element is also used in atomic-hydrogen energy during the thermochemical decomposition of water.
Harm and effect on humans
Small amounts of europium are found in the human body. It can also be contained in water, falling into it in the areas of mineral deposits, of which it is a part. Industrial production also supplies water with this element.
The effect of the element on the body and human health has not been studied. Trusting the widespread information, it does not pose any particular danger, since its concentration, as a rule, is too small.
Europium has very little toxicity, and its content in water is usually so insignificant that it is not able to significantly affect its quality. In fresh and low-saline waters, its amount reaches 1 mcg / L; in seawater, this indicator is 1.1 * 10 -6 mg / L.