Showing posts with label radium. Show all posts
Showing posts with label radium. Show all posts

Saturday, 4 July 2020

MARIE CURIE, THE FIRST WOMAN TO WIN A NOBEL PRIZE

Marie Curie
Today, The Grandma has been reading about Marie Skłodowska Curie, the Polish physicist and chemist who conducted pioneering research on radioactivity.

Marie Curie was the first woman to win the Nobel Prize in history and she is recognized as one of the greatest name in science.

Marie Curie died on a day like today in 1934 and The Grandma thinks that the best way to pay tribute to her is talking about her life and her career.

Marie Skłodowska Curie (7 November 1867-4 July 1934) was a Polish and naturalized-French physicist and chemist who conducted pioneering research on radioactivity.


She was the first woman to win a Nobel Prize, the first person and the only woman to win the Nobel Prize twice, and the only person to win the Nobel Prize in two different scientific fields.

She was part of the Curie family legacy of five Nobel Prizes. She was also the first woman to become a professor at the University of Paris, and in 1995 became the first woman to be entombed on her own merits in the Panthéon in Paris.

She was born in Warsaw, in what was then the Kingdom of Poland, part of the Russian Empire. She studied at Warsaw's clandestine Flying University and began her practical scientific training in Warsaw.


More information: Marie Curie

In 1891, aged 24, she followed her older sister Bronisława to study in Paris, where she earned her higher degrees and conducted her subsequent scientific work.


She shared the 1903 Nobel Prize in Physics with her husband Pierre Curie and physicist Henri Becquerel. She won the 1911 Nobel Prize in Chemistry.

Her achievements include the development of the theory of radioactivity, a term she coined, techniques for isolating radioactive isotopes, and the discovery of two elements, polonium and radium. Under her direction, the world's first studies were conducted into the treatment of neoplasms using radioactive isotopes.


She founded the Curie Institutes in Paris and in Warsaw, which remain major centres of medical research today. During World War I she developed mobile radiography units to provide X-ray services to field hospitals.

Marie Curie
While a French citizen, Marie Skłodowska Curie, who used both surnames, never lost her sense of Polish identity. She taught her daughters the Polish language and took them on visits to Poland. She named the first chemical element she discovered polonium, after her native country.

Marie Curie died in 1934, aged 66, at a sanatorium in Sancellemoz (Haute-Savoie), France, of aplastic anaemia from exposure to radiation in the course of her scientific research and in the course of her radiological work at field hospitals during World War I.

Maria Skłodowska was born in Warsaw, in Congress Poland in the Russian Empire, on 7 November 1867, the fifth and youngest child of well-known teachers Bronisława, née Boguska, and Władysław Skłodowski.

In late 1891, she left Poland for France. In Paris, Maria or Marie, as she would be known in France briefly found shelter with her sister and brother-in-law before renting a garret closer to the university, in the Latin Quarter, and proceeding with her studies of physics, chemistry, and mathematics at the University of Paris, where she enrolled in late 1891.


She subsisted on her meagre resources, keeping herself warm during cold winters by wearing all the clothes she had. She focused so hard on her studies that she sometimes forgot to eat.

More information: Live Science

Skłodowska had begun her scientific career in Paris with an investigation of the magnetic properties of various steels, commissioned by the Society for the Société d'encouragement pour l'industrie national).

That same year Pierre Curie entered her life; it was their mutual interest in natural sciences that drew them together. Pierre Curie was an instructor at The City of Paris Industrial Physics and Chemistry Higher Educational Institution.

They were introduced by the Polish physicist, Professor Józef Wierusz-Kowalski, who had learned that she was looking for a larger laboratory space, something that Wierusz-Kowalski thought Pierre Curie had access to. Though Curie did not have a large laboratory, he was able to find some space for Skłodowska where she was able to begin work.


Pierre & Marie Curie
In 1895, Wilhelm Roentgen discovered the existence of X-rays, though the mechanism behind their production was not yet understood.

In 1896, Henri Becquerel discovered that uranium salts emitted rays that resembled X-rays in their penetrating power. He demonstrated that this radiation, unlike phosphorescence, did not depend on an external source of energy but seemed to arise spontaneously from uranium itself. Influenced by these two important discoveries, Curie decided to look into uranium rays as a possible field of research for a thesis.

In December 1903, the Royal Swedish Academy of Sciences awarded Pierre Curie, Marie Curie, and Henri Becquerel the Nobel Prize in Physics, in recognition of the extraordinary services they have rendered by their joint researches on the radiation phenomena discovered by Professor Henri Becquerel.

At first the committee had intended to honour only Pierre Curie and Henri Becquerel, but a committee member and advocate for women scientists, Swedish mathematician Magnus Goesta Mittag-Leffler, alerted Pierre to the situation, and after his complaint, Marie's name was added to the nomination. Marie Curie was the first woman to be awarded a Nobel Prize.

Curie visited Poland for the last time in early 1934. A few months later, on 4 July 1934, she died at the Sancellemoz sanatorium in Passy, Haute-Savoie, from aplastic anaemia believed to have been contracted from her long-term exposure to radiation.


More information: Culture

The damaging effects of ionising radiation were not known at the time of her work, which had been carried out without the safety measures later developed. She had carried test tubes containing radioactive isotopes in her pocket, and she stored them in her desk drawer, remarking on the faint light that the substances gave off in the dark.

Curie was also exposed to X-rays from unshielded equipment while serving as a radiologist in field hospitals during the war. Although her many decades of exposure to radiation caused chronic illnesses, including near-blindness due to cataracts, and ultimately her death, she never really acknowledged the health risks of radiation exposure.

She was interred at the cemetery in Sceaux, alongside her husband Pierre. Sixty years later, in 1995, in honour of their achievements, the remains of both were transferred to the Panthéon, Paris. Their remains were sealed in a lead lining because of the radioactivityShe became the first woman to be honoured with interment in the Panthéon on her own merits.

Because of their levels of radioactive contamination, her papers from the 1890s are considered too dangerous to handle. Even her cookbook is highly radioactive. Her papers are kept in lead-lined boxes, and those who wish to consult them must wear protective clothing.


In her last year, she worked on a book, Radioactivity, which was published posthumously in 1935.

More information: Famous People Lessons


Nothing in life is to be feared,
it is only to be understood.
Now is the time to understand more,
so that we may fear less.

Marie Curie

Wednesday, 26 December 2018

MARIE & PIERRE CURIE: THE ISOLATIUM OF RADIUM

Radium
Today, The Grandma has been resting after the Christmas dinner. She has decided to read a little about two important scientists who she admires a lot, Marie and Pierre Curie.

The Curies announced their discovery to the French Academy of Sciences on a day like today in 1898. Before reading about The Curies, The Grandma has studied a new lesson of her Elementary Language Practice manual (Grammar 54 & Checkpoint 9). 

More information: Pronouns 2

Radium is a chemical element with symbol Ra and atomic number 88. It is the sixth element in group 2 of the periodic table, also known as the alkaline earth metals. Pure radium is silvery-white, but it readily reacts with nitrogen, rather than oxygen, on exposure to air, forming a black surface layer of radium nitride (Ra3N2). All isotopes of radium are highly radioactive, with the most stable isotope being radium-226, which has a half-life of 1600 years and decays into radon gas, specifically the isotope radon-222. When radium decays, ionizing radiation is a product, which can excite fluorescent chemicals and cause radioluminescence.

Radium, in the form of radium chloride, was discovered by Marie and Pierre Curie in 1898. They extracted the radium compound from uraninite and published the discovery at the French Academy of Sciences five days later. Radium was isolated in its metallic state by Marie Curie and André-Louis Debierne through the electrolysis of radium chloride in 1911.

Pierre Curie
In nature, radium is found in uranium and, to a lesser extent, thorium ores in trace amounts as small as a seventh of a gram per ton of uraninite. Radium is not necessary for living organisms, and adverse health effects are likely when it is incorporated into biochemical processes because of its radioactivity and chemical reactivity.

Currently, other than its use in nuclear medicine, radium has no commercial applications; formerly, it was used as a radioactive source for radioluminescent devices and also in radioactive quackery for its supposed curative powers. Today, these former applications are no longer in vogue because radium's toxicity has since become known, and less dangerous isotopes are used instead in radioluminescent devices.

Radium is the heaviest known alkaline earth metal and is the only radioactive member of its group. Its physical and chemical properties most closely resemble its lighter congener barium.

More information: American Physical Society

Pure radium is a volatile silvery-white metal, although its lighter congeners calcium, strontium, and barium have a slight yellow tint. Its color rapidly vanishes in air, yielding a black layer of radium nitride (Ra3N2). Its melting point is either 700 °C or 960 °C and its boiling point is 1,737 °C. Both of these values are slightly lower than those of barium, confirming periodic trends down the group 2 elements. Like barium and the alkali metals, radium crystallizes in the body-centered cubic structure at standard temperature and pressure: the radium–radium bond distance is 514.8 picometers.

Radium has a density of 5.5 g/cm3, higher than that of barium, again confirming periodic trends; the radium-barium density ratio is comparable to the radium-barium atomic mass ratio, due to the two elements' similar crystal structures.

Marie Curie
Radium was discovered by Marie Sklodowska-Curie and her husband Pierre Curie on 21 December 1898, in a uraninite, pitchblende, sample. While studying the mineral earlier, the Curies removed uranium from it and found that the remaining material was still radioactive.

They separated out an element similar to bismuth from pitchblende in July 1898, which turned out to be polonium. They then separated out a radioactive mixture consisting mostly of two components: compounds of barium, which gave a brilliant green flame color, and unknown radioactive compounds which gave carmine spectral lines that had never been documented before.

The Curies found the radioactive compounds to be very similar to the barium compounds, except that they were more insoluble. This made it possible for the Curies to separate out the radioactive compounds and discover a new element in them. The Curies announced their discovery to the French Academy of Sciences on 26 December 1898. The naming of radium dates to about 1899, from the French word radium, formed in Modern Latin from radius (ray): this was in recognition of radium's power of emitting energy in the form of rays.

More information: Nobel Prize

On September 1910, Marie Curie and André-Louis Debierne announced that they had isolated radium as a pure metal through the electrolysis of a pure radium chloride (RaCl2) solution using a mercury cathode, producing a radium–mercury amalgam. This amalgam was then heated in an atmosphere of hydrogen gas to remove the mercury, leaving pure radium metal. Later that same year, E. Eoler isolated radium by thermal decomposition of its azide, Ra(N3)2.

Radium metal was first industrially produced in the beginning of the 20th century by Biraco, a subsidiary company of Union Minière du Haut Katanga (UMHK) in its Olen plant in Belgium.

Pierre & Marie Curie
The common historical unit for radioactivity, the curie, is based on the radioactivity of 226Ra.

Some of the few practical uses of radium are derived from its radioactive properties. More recently discovered radioisotopes, such as cobalt-60 and caesium-137, are replacing radium in even these limited uses because several of these isotopes are more powerful emitters, safer to handle, and available in more concentrated form.

The isotope 223Ra, under the trade name Xofigo, was approved by the United States Food and Drug Administration in 2013 for use in medicine as a cancer treatment of bone metastasis. The main indication of treatment with Xofigo is the therapy of bony metastases from castration-resistant prostate cancer due to the favourable characteristics of this alpha-emitter radiopharmaceutical. 225Ra has also been used in experiments concerning therapeutic irradiation, as it is the only reasonably long-lived radium isotope which does not have radon as one of its daughters.

More information: Factinate

Radium is still used today as a radiation source in some industrial radiography devices to check for flawed metallic parts, similarly to X-ray imaging. When mixed with beryllium, radium acts as a neutron source.

Radium-beryllium neutron sources are still sometimes used even today, but other materials such as polonium are now more common: about 1500 polonium-beryllium neutron sources, with an individual activity of 1,850 Ci (68 TBq), have been used annually in Russia. These RaBeF4-based (α, n) neutron sources have been deprecated despite the high number of neutrons they emit, 1.84×106 neutrons per second, in favour of 241Am–Be sources. Today, the isotope 226Ra is mainly used to form 227Ac by neutron irradiation in a nuclear reactor.



When radium was discovered, no one knew that it would prove 
useful in hospitals. The work was one of pure science. 
And this is a proof that scientific work must not be 
considered from the point of view of the direct usefulness of it. 

Marie Curie