Radium

Radium, a radioactive element, was first discovered by the esteemed scientists Marie and Pierre Curie. Between them, Marie and Pierre Curie shook the scientific world. Their work on radium and radioactivity paved the way for further research on radioactive elements and their potential applications, with significant consequences for the wider world.

Radium is formed through the radioactive decay of uranium and thorium. It can be found in uranium ores and thorium ores. Less than 100 grams of radium is produced annually.

Radium has had various applications throughout history. One of the most notable uses of radium was in luminous paints for watches, aircraft switches, and instrument dials. The radioactivity of radium causes it to glow, making it seemingly ideal for use in these applications where visibility in low light conditions is crucial.

The discovery of radium was made by Marie Curie and Pierre Curie in 1898. In the same year, they discovered another new radioactive element - polonium. Marie Curie coined the term ‘radioactive’ to describe these elements that emitted energy through atomic decay.

The Curies' discovery of radium was a result of their extensive research on a mineral called pitchblende, which is primarily composed of uranium. They managed to extract 1mg of radium from ten tonnes of pitchblende, demonstrating the rarity and difficulty of extracting radium in significant quantities.

Marie Curie's work on radium earned her two Nobel prizes, making her the first woman to receive a Nobel prize and the first person to receive a second Nobel prize. She was awarded her first Nobel prize in Physics in 1903, shared with Pierre Curie and Henri Becquerel, for their research on radiation. She received her second Nobel prize in Chemistry in 1911.

Tragically, Marie Curie’s foundational work in the study of radioactivity was also the cause of her death. She spent many years working with radioactive substances such as radium, before the extremely dangerous effects of such substances were widely understood. This was almost certainly a factor in her eventual death from aplastic anemia.

Radium is formed by the radioactive decay of uranium and thorium. This process involves radioactive atoms giving off radiation in the form of energy or particles to reach a stable state. This decay process is a fundamental aspect of radioactivity and is responsible for the creation of many radioactive elements, including radium.

Pure radium is silvery white. When it’s exposed to air, it reacts quickly with nitrogen. This reaction produces radium nitride which creates a black surface layer.

Radium has 88 protons in its atomic nucleus, which gives it the atomic number 88. It has 33 known isotopes. The most common of these are Ra-226 and Ra-228, which are produced by the radioactive decay of uranium and thorium respectively.

These isotopes are distinguished by the number of neutrons in their atomic nucleus. Despite having different numbers of neutrons, all isotopes of an element share the same number of protons and thus have the same atomic number.

Radium is known for its high radioactivity. This radioactivity is what makes radium both useful and hazardous.

But what does radioactivity actually mean? In simple terms, it is where an element’s atoms are unstable, and therefore emit particles and energy from their nucleus.

In the last section we discussed isotopes – meaning versions of the same atoms that have differing numbers of neutrons. A nucleus will be more or less stable depending upon its relative numbers of neutrons and protons. In the case of radium, many isotopes, such as Ra-226, are unstable. As a result, the atoms are prone to firing out particles to try to stabilise their nuclei.

It is this emission of particles that is known as ‘radiation’, and it can be highly dangerous. There are many elements in the periodic table that are radioactive. Mostly they appear at the bottom of the table.

Radium is produced during the radioactive decay of uranium and thorium in the Earth's crust. This natural process is responsible for the presence of radium in the environment, albeit in trace amounts. Radium undergoes radioactive decay to produce the inert gas radon.

All primordial radium originally present on Earth will have decayed already, meaning that any radium currently present is a result of ongoing radioactive decay processes.

Despite its decay, radium is still present in tiny quantities in the environment. One kilogram of Earth's crust typically contains about 900 picograms of radium, while a liter of seawater contains around 89 femtograms. These are incredibly tiny amounts, but it's there. Commercially, radium is typically only available in the compounds radium chloride or radium bromide due to the difficulty of isolating pure radium.

Uranium ores from the Democratic Republic of the Congo and Canada are the richest sources of radium today, but annual production of radium is only around 100 grams in total.

Despite its radioactivity, radium found its way into various commercial and industrial applications. The unique properties of radium, such as its radioactivity and luminescence, made it a sought-after resource in a variety of fields.

Radium was once used to make luminous paints for objects such as clocks, watches, and airplane controls. The glow produced by radium made these objects visible in low light conditions, making it a useful tool for the job. However, due to the health risks associated with radium, it is now considered too hazardous to be used in this way.

Historically, radium has been used in the treatment of cancer, particularly via the production of radon gas. Radium-223 is sometimes used now to treat prostate cancer that has spread to the bones. This isotope of radium emits alpha particles, which can kill cancer cells. However, in general, radium is not commonly used in modern cancer treatments due to its instability and rarity. Other more stable radioactive elements are typically used instead.

Radium poses a significant health hazard due to its radioactivity. Exposure to radium can increase the risk of some types of cancer, and higher doses of radium have been shown to affect the blood, eyes, teeth, and bones.

The harmful effects of radium were made clear very soon after the element’s discovery, with the first case of ‘radium dermatitis’. In 1910, the French scientist Antoine Becquerel carried a vial of radium in the pocket of his waistcoat for 6 hours. His skin became ulcerated as a result.

One of the decay products of radium, radon gas, is also a health hazard. When radon gas is inhaled, radioactive particles can get trapped in your lungs, increasing the risk of lung cancer over time. This risk is particularly high in areas with high levels of radium in the soil and rock.

The dangers of radium and its decay products have led to strict regulations on its use and disposal. These regulations are designed to protect people and the environment from the harmful effects of radium and other radioactive substances.

The Radium Girls were factory workers who contracted radiation poisoning from painting watch dials with self-luminous paint containing radium. Their story is a tragic example of the dangers of radium and the lack of safety measures in place at the time. Women at the three factories involved in the USA were told the radium-based paint was safe, and they even put the brushes in their mouths to give them a fine tip.

This practice led to the ingestion of radium, which resulted in severe health problems for these women. The symptoms experienced by the Radium Girls included anemia, bone fractures, and necrosis of the jaw. Their experience led to significant changes in labor laws and safety standards for workers handling radioactive materials. This tragic event serves as a stark reminder of the dangers of radium and the importance of proper safety measures when handling radioactive substances.