Themes

Yttrium: structure, properties, uses, obtaining

Yttrium and lanthanides are present in the same minerals, including bastnäsite and monazite. It is a relatively stable metal in air, due to a layer of its oxide that gives it protection, but it oxidizes quickly in hot air.

Dendritic crystals of metallic yttrium and ultrapure. Source: Jurii, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0>, via Wikimedia Commons

It forms compounds predominantly with the oxidation state +3 (Y 3+ ), such as yttrium oxide, Y 2 O 3 , and compounds that are soluble or insoluble in water.

Yttrium was discovered in 1794 by Johan Gadolin, a Finnish scientist who analyzed a dark mineral given by Carl Arrhenius himself. Gadolin found an unknown element in the mineral, his findings being confirmed by the Swedish chemist Anders Ekeberg, who named the oxide of the new metal ‘yttria’, while he called the metal ‘yttrium’.

Structure

The yttrium atoms are joined by the metallic bond to form a compact hexagonal structure (hcp). This structure corresponds to one of its two allotropic forms: the α phase, which is stable at room temperature. However, when yttrium crystals are heated to 1478 ° C, they adopt a cubic structure, called the β phase.

Electronic configuration

Yttrium has the following electronic configuration:

[Kr] 4d 1  5s 2

Therefore, it has three valence electrons with which to establish its metallic bond. Likewise, it can lose these three electrons to become the cation Y 3+ , which is isoelectronic with the noble gas krypton.

Yttrium properties

Isolated yttrium

Physical appearance

Odorless, lustrous, highly crystalline, silvery-white solid metal available as a dark gray powder.

Atomic number

39

Molar mass

89.905 g / mol

Melting point

1526 ºC

Boiling point

2930 ºC

Density

4.472 g / cm 3

Heat of fusion

11.42 kJ / mol

Heat of vaporization

363 kJ / mol

Molar caloric capacity

26.53 J / (mol K)

Oxidation states

Yttrium can participate in its compounds with any of the following oxidation states: 0, +1, +2 and +3, with +3 being the most common as it is a group 3 element.

1.22 on the Pauling scale

Ionization energies

First: 600 kJ / mol

Second: 1180 kJ / mol

Third: 1980 kJ / mol

Magnetic order

It is a paramagnetic metal, however it becomes a superconductor at a temperature of -271.9 ºC and under pressures above 110 kilobars.

Reactivity and compounds

The pure element is quite stable, because yttrium oxide, Y 2 O 3 , forms a protective layer on the metal surface. However, it can oxidize rapidly in air at temperatures above 450ºC. If it is pulverized, it burns even at lower temperatures.

Yttrium forms inorganic compounds with the oxidation state +3; for example: Y 2 O 3 , Y (OH) 3 , Y 2 (C 2 O 4 ) 3 , YPO 4 , YF 3 , etc.

Reacts rapidly with strong acids, except for nitric and hydrofluoric acids. Likewise, it reacts with halogens at temperatures above 200 ºC, to form halides.

On the other hand, at high temperatures it forms binary compounds with phosphorus, selenium, carbon, phosphorus, silicon and sulfur. Yttrium can be part of organic chemical compounds.

The yttrium ion, Y 3+ , is colorless in solution, as are its oxide, trichloride, sulfate, and carbonate.

Applications

Color television

Yttrium oxide or yttrium sulfide, Y 2 S 3 , doped with the element europium, are involved in the production of the color red in color televisions that use cathode tubes.

Garnets

Yttrium iron garnet. Source: Krizu at German Wikipedia, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons

Yttrium Aluminum Garnet (YAG), doped with cerium, is used in phosphors and white LEDs. It is also used, given its hardness, as an imitation of diamond. Furthermore, the YAG laser, due to its energy, is used for drilling and cutting metals.

Meanwhile, yttrium iron garnet (YIG) is used as a microwave filter and in the transmission of acoustic energy.

Alloys

Yttrium is used to increase the strength of aluminum and magnesium alloys. Yttrium oxide, meanwhile, combines with zirconium oxide to form an alloy that intervenes in the formation of a very resistant ceramic; ceramic used in electronics, as well as in the formation of a thermal barrier for jet engines.

An alloy of yttrium with chromium and aluminum is used in the production of a highly heat resistant electrical conductor.

Doctors

The radioactive isotope of yttrium, 90 Y, has been used in the treatment of many types of cancer. The 90 Y is a radioactive emitter β particles with an average life of 2.67 days (64.1 hours).

It is used to treat different types of cancer, such as lymphoma and leukemia, which affect white blood cells. Also, for liver, ovarian, colon-rectal, pancreatic and bone cancer.

The 90 Y is administered, using various modalities, through the blood vessels that carry blood to the tissues where the cancerous tumor is present.

It can bind to monoclonal antibodies directed specifically against tumor cells. By binding the antibodies to tumor cells, it allows the attachment of 90 Y to them, thus allowing their destruction. Microspheres are also used to transport the isotope to cancerous tissue.

This technique is called radioembolization, and the 90 Y- containing spheres are injected into the blood vessels that lead to the cancerous liver tissue. In addition, 90 Y is attached to tiny needles used to treat swollen joints, especially in the knees.

Ceramics and glass

Yttrium is used in the production of silicon nitride, a compound used to make a ceramic with a hardness of 8.5 (Mohs scale), used in kiln pieces. Yttrium oxide is used in the manufacture of a glass and a ceramic with low thermal expansion.

Pigment

Recent and non-toxic bluish pigment that contains yttrium atoms in its composition. Source: Mas Subramanian, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons

One of the relatively more recent (2009) uses of yttrium is as a component in the preparation of a pigment: YInMn blue (image above), discovered by researchers at the University of Oregon. Its formula is YIn 1-x Mn x O 3 , and therefore its crystalline structure is composed of the oxides of yttrium, indium and manganese.

YInMn blue is the last pigment to have been discovered after cobalt blue, CoAl 2 O 4 , two hundred years ago, in 1802. It is characterized, as can be seen, by its vibrant and modifiable colors. In addition, it is a stable and non-toxic pigment.

Others

There are yttrium compounds that are used as catalysts for the polymerization of ethylene. Metallic yttrium is used to make electrodes in high-performance spark plugs. It is also used to deoxidize vanadium and other non-ferrous metals.

Yttrium is part of a copper, barium and yttrium oxide superconductor, known as “YBCO”. In this superconductor, liquid nitrogen is used to lower the temperature instead of helium, thus reducing costs.

Yttrium is incorporated into the cathodes of some lithium iron phosphate (LFP) batteries.

Obtaining

Yttrium has an abundance of 33 ppm in the earth’s crust. It is found forming part of some minerals along with elements of the rare earths. It is commercially exploited from monazite, which contains 3% of the metal, and bastnäsite, with 0.2% of it.

However, it is also found in minerals such as gadolinite, euxenite, and Malaysian xenotime, which contains up to 60% yttrium as phosphate.

Yttrium oxide can be obtained from a mixture with rare earth element oxides, dissolving the material containing them in sulfuric acid and then fractionating them by ion exchange chromatography.

Yttrium can be purified by a method that uses oxalic acid and that ultimately produces yttrium fluoride, after the intervention of hydrogen fluoride. Yttrium fluoride is reduced to metallic yttrium by reduction using calcium as a reducing agent at elevated temperatures.

Isotopes

Yttrium has a total of 33 isotopes, whose masses range from 76 Y to 108 y. The only stable isotope is 89 Y, while the remaining isotopes are radioactive, most of which emit beta particles (β  and β + ). The least stable radioactive isotope is 106 Y, with a half-life of less than 150 nanoseconds.

Meanwhile, the most stable radioactive isotope is 88 Y, with a half-life of 106,626 days. Most radioactive isotopes of yttrium have a half-life of less than 1 hour.

Related Articles

Leave a Reply

Your email address will not be published. Required fields are marked *

Back to top button