Einsteinium

Einsteinium

Einsteinium is a special material that scientists make in labs. It is not found in nature. Its symbol is Es and it has an atomic number of 99. Einsteinium is part of a group called the actinides and is made after uranium.

Einsteinium was first found in 1952 after a big explosion from a hydrogen bomb test. The most common form, einsteinium-253, is made in powerful nuclear reactors. Only very small amounts are made, about one milligram each year, and it is hard to separate from other materials. Because there is so little of it and it does not last long, einsteinium is mostly used for basic science tests. For example, it helped scientists make a new element called mendelevium in 1955.

Einsteinium looks like a soft, shiny metal and glows because it is very radioactive. It is hard to study because it changes quickly into other elements. It can be dangerous if swallowed because of its radioactivity.

History

Einsteinium was first found in December 1952 by Albert Ghiorso and his team at the University of California, Berkeley. They discovered it in the fallout from the Ivy Mike nuclear test on November 1, 1952, at Enewetak Atoll in the Pacific Ocean. This was the first test of a very powerful thermonuclear weapon.

The scientists looked at materials from the explosion and found a new type of plutonium. This showed that more neutrons could be captured to make heavier elements than californium.

Ghiorso’s team studied materials from the explosion and later found more from coral debris. They used special chemistry to separate the new elements and found einsteinium-253 (253Es) through its high-energy alpha decay.

Some uranium atoms captured even more neutrons, leading to einsteinium-255 (255Es) and fermium-255 (255Fm). The discovery stayed secret until 1955 because of Cold War tensions. The findings helped confirm ideas about how heavy elements form in space.

The Berkeley team also made einsteinium in labs using nuclear reactions. They suggested naming the element after Albert Einstein and Enrico Fermi. The name einsteinium (Es) was announced at the Geneva Atomic Conference in August 1955.

Characteristics

Einsteinium is a man-made, shiny, radioactive metal. It is found on the periodic table between the actinides californium and fermium, and below the lanthanide holmium. It has a density of 8.84 g/cm³, which is lighter than californium but similar to holmium. Einsteinium melts at a relatively low temperature of 860 °C.

Unlike some other actinides, einsteinium is thought to have a special cube shape in its structure. However, its strong radioactivity breaks down its structure quickly, making it glow. Because samples are very tiny and hard to study, scientists heat the metal to see its properties better. Einsteinium is also very reactive and can be in different chemical states, which is rare for actinides.

The most stable type of einsteinium, ²⁵²Es, lasts for 471.7 days before it changes. All types of einsteinium are radioactive and break down fast. Because of this, einsteinium does not exist in nature and must be created in labs or nuclear reactors.

Synthesis and extraction

Einsteinium is made in very small amounts by using strong nuclear tools to change lighter elements. Two main places where this happens are the High Flux Isotope Reactor in Tennessee, U.S., and the SM-2 loop reactor in Russia. These reactors can make very heavy elements, but only tiny bits are produced each year.

In the past, scientists made a very small amount of einsteinium in 1961. Later, they made more, but it was still just a little bit. Making einsteinium needs special tools and careful work.

Laboratory synthesis

Scientists can make einsteinium in different ways in labs. One way is by using plutonium and very strong neutron beams. Another way is to use uranium and send special particles at it.

In 1967, scientists in Russia made a new type of einsteinium by using special tools. They used americium and carbon, or uranium and nitrogen, to create it.

Synthesis in nuclear explosions

Scientists also looked at debris from big nuclear tests to see if they could find einsteinium. These tests created very strong conditions that could make heavy elements, but it was hard to collect the material.

Separation

Getting einsteinium from the mix of materials made during these processes is very difficult. Scientists use special steps to separate it, like using chemicals and heat. They need to separate it from other similar elements.

Preparation of the metal

To get pure einsteinium metal, scientists use strong reducing agents. One way is to use lithium to change einsteinium fluoride into metal. Another way is to use lanthanum metal to change einsteinium oxide into metal, which works better.

Chemical compounds

Oxides

Einsteinium(III) oxide (Es₂O₃) is made by burning einsteinium(III) nitrate. It forms clear cubic crystals. There are two other crystal shapes for this oxide, and which shape forms depends on how it is made. The crystal shape where Es³⁺ is surrounded by six O²⁻ ions is similar to lanthanum oxide.

Halides

Einsteinium can form compounds called halides in two different states. The most stable state for all halides, from fluoride to iodide, is +3.

Einsteinium(III) fluoride (EsF₃) can be made by mixing Es(III) chloride with fluoride ions or by using special gases.

Es(III) chloride (EsCl₃) is made by heating Es(III) oxide with dry hydrogen chloride gas. It forms an orange solid.

The less common, +2 state compounds of einsteinium are made by using hydrogen to change the +3 halides.

Some compounds called oxyhalides, like EsOCl, EsOBr and EsOI, are made by mixing a trihalide with water vapor and a hydrogen halide.

Organoeinsteinium compounds

Because einsteinium is very radioactive, it might be used in medical treatments to target specific parts of the body. Scientists have made special compounds to deliver einsteinium. Einsteinium ions were seen to glow in certain solutions.

Applications

Einsteinium is mostly used for basic science experiments, especially to make heavier elements.

In 1955, scientists used einsteinium to create a new element called mendelevium. They aimed a beam of particles at einsteinium and made 17 atoms of this new element.

A special type of einsteinium called <sup>254</sup>Es is helpful for making even heavier elements because it lasts longer and can be found in small amounts. Scientists tried to use it to make an element called ununennium, but they didn’t find any atoms of it.

This einsteinium isotope was also used on a moon probe to help scientists study the surface of the Moon. Its heavy mass helped the instruments work better.

Safety

We learn about einsteinium's effects on health mostly from animal studies. When rats ate einsteinium, only a tiny bit entered their blood. Most of it went to their bones and stayed there for years. Some went to the lungs, and a very small amount went to the reproductive organs. About 10% left the body. The way einsteinium spreads in bones is similar to an element called plutonium.