Mendelevium: Properties, Isotopes, Synthesis & Uses

Mendelevium is a synthetic highly radioactive element. It is named after Dimtri Mendeleyev, the father of the periodic table of chemical elements. Mendelevium isotopes have unique chemical properties for late actinides, having a predominant +3 oxidation state and a neighbouring +2 oxidation state. It is used in the synthesis of heavy atomic nuclei. It decays through the process of spontaneous fission and hence the traces are not found in the atmosphere. Humans are adversely affected due to the active radiation emitted by the element. 

Read more: Inner Transition Elements 

Key terms: Mendelevium, f-block elements, Transuranium, Actinides, Transition elements, Oxidation Reaction

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What is Mendelevium?

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Structure of Mendelevium

The most stable isotope of mendelevium, ²⁵⁸Md, has a half-life of 52 days and is the first transferium element. Chemical information about it is limited to its atomic number, half-life, and isotopes. Isotopes with known atomic weights range from 245 to 261. It was named after Dimitri Mendeleyev, a Russian physicist who created one of the earliest periodic tables. 

Mendelevium is a synthetic highly radioactive actinide element. It has the symbol Md and the atomic number 101. The only way to make it is to blast lighter elements with charged molecules. Bernard G Harvey, Stanley G Thompson, Albert Ghiorso, Glenn T. Seaborg, and Gregory R Choppin, all of the University of California, Berkeley, discovered the element in 1955. They found it by blasting alpha particles (helium ions) with a trace of einsteinium-253. 

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Properties of Mendelevium

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The Physical and Chemical properties of the element are mentioned below.

Physical Properties

Physical Properties of the Mendelevium are as follows:

Chemical Properties

• Chemical reactions have only been carried out in solutions having oxidation states of +2 or +3 until now. Though the +1 condition has been discovered, it has yet to be proven.
• In an aqueous solution, it is trivalent.
• It condenses trivalent lanthanide salts to create insoluble fluorides and hydroxides.
• During carbon-exchange bonding, the mendelevium elutes.
• Its ionic radius is lower than that of the previous actinide in the periodic table (Fermium).
• Mendelevium(III) is easily converted to Mendelevium(II). In an aqueous solution, it has a steady behavior.
• In a water-ethanol solution, it is neutral and similar or homologous to cesium.
• When reduced, it behaves like divalent elements.
• Mendelevium crystallizes in mixed crystals with divalent elements when co-crystallized with chlorides.
• It has a proclivity for deterioration.
• It contains 16 synthetic isotopes with mass numbers ranging from 245-260.

Mendelevium Structure

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Isotopes

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Isotopes are members of the same element's family but have variable numbers of neutrons despite having the same number of protons.

• Mendelevium is divided into 16 isotopes with mass numbers ranging from ²⁴⁵Md to ²⁶⁰Md. 
• ²⁵⁸Md, ²⁶⁰Md, and ²⁵⁹Md are the longest-lived isotopes of mendelevium, with half-lives of 51.5 days, 31.8 days, and 96 minutes, respectively.
• After Md-245, the longevity of Md isotopes increases, but then declines after Md-256.

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Production in Laboratories

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Mendelevium production in laboratories are done in following steps

• The distinct elution characteristics of Md from those of einsteinium and fermium are used in an alternate approach to isolate Mendelevium.

Atomic Structure of Einsteinium

• The preliminary stages are the same as before, except that instead of lanthanum fluoride, HDEHP is used for abstraction chromatography, and the mendelevium is coprecipitated with terbium fluoride. 
• The Mendelevium is then given Chromium to condense it in hydrochloric acid with Zinc or Mercury.
• Even though the tetravalent lanthanides, trivalent lanthanides, and actinides remain on the column after solvent extraction, it is oxidized to the +3-state using hydrogen peroxide
• It is then isolated by elution with hydrogen peroxide (to remove contaminants and chromium) and lastly hydrochloric acid (to extract the mendelevium).
• Use zinc and cationic amalgam column with 1 M hydrochloric acid as an eluent to reduce Mendelevium(III) to Md(II), where it behaves like alkaline metals.
• Mendelevium is synthesized in the same way since it was eluted the first time. Bismuth is bombarded with strong Argon ions in a 60-inch cyclotron to create the lightest isotopes ²⁴⁵Md through ²⁴⁷Md.
• The cyclotron produces slightly heavier isotopes by bombarding Plutonium with Carbon ions and Americium with Nitrogen ions. Einsteinium is bombarded with alpha particles to yield the most stable 258Md isotope.
• Produced Md's recoil momentum separates it from the einsteinium target. Then it's vacuum-sealed onto a thin metal foil. This method eliminates the requirement for chemical separation right away.
• Fission products are used to extract Md atoms from metal foil. The Md atoms are then trapped in a gaseous environment, which is carried along by a jet of gas. Md atoms are transferred over a short distance using capillary tubes containing potassium chloride aerosols in helium gas.

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Uses of Mendelevium

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Applications of Mendelevium are as follows

• The metal has no practical or economic applications because it is not manufactured in large quantities.
• The isotope ²⁵⁶Md is used for scientific research and to analyze the chemical characteristics of various elements and aqueous solutions.
• It is used in the synthesis of heavy atomic nuclei.

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Points To Remember

• In addition to a trivalent state, it has a reasonably stable divalent state.
• In water-ethanol solutions, it can be reduced to a monovalent state.
• Mendelevium is a highly radioactive metal that is dangerous when ingested.
• It is not known to have any environmental impact because it is not formed on the earth's crust.