In 1897, at the age of 30, Maria Skłodowska, who married Pierre Curie in 1895, finished her studies at the Sorbonne in Paris and was thinking about the subject of her dissertation. The X-rays discovered by Wilhelm Conrad Roentgen in 1895 were still a hot topic, but they had lost their novelty charm.
On the other hand, uranium rays, discovered in 1896 by Henri Becquerel, caused a mysterious problem. Uranium compounds and minerals seem to be able to improve their ability to survive for several months. What was the source of this inexhaustible energy, which, apparently, violated the Carnot principle, which cannot be transformed or destroyed? Pierre Curie, already a well-known physicist for his work on magnetism and crystal symmetry, felt that this phenomenon was rather unusual, and he helped his wife solve it. Marie Curie, in a biography of Pierre Curie, confirmed: "We believe that the study of this phenomenon is very attractive, so there is a need for new bibliographic studies." And today we will find out who discovered radium.
Conductive electricity
After the initial excitement, interest in the new rays faded quickly. One of the reasons was the spread of false or questionable observations of radiation, similar to uranium rays in various substances. No one thought about who discovered radium. The theme was "dead" when Marie Curie entered the scene. However, within eight months in 1898, she discovered two elements: polonium and radium, creating a new scientific field - radioactivity. This short history of discoveries goes back to three laboratories, in which the work of Pierre and Marie can be distinguished and from three notes published in the Proceedings of the Academy of Sciences. In addition to blackening the photographic plate, the uranium rays produced air that conducts electricity. This later property was much more quantifiable. Becquerel used electroscopes, but the measurements were unreliable. This explains who discovered radium.
Uranium rays
At this point there would be no progress without the genius of Pierre Curie. If not for him, no one would have wondered who discovered radium. In 1880, with his brother Jacques, he discovered piezoelectricity (i.e., the production of electrical charges when applied to hemihedral crystals such as quartz). He invented a device by which the charges produced by uranium in an ionization chamber were offset by the use of quartz. The compensation was followed by a second invention, the quadrant electrometer. Radiationuranium rays could be quantified by the weight and time required to compensate for the charges created in the ionization chamber.
First report
Report by Marie Curie published April 12, 1898 in the Proceedings of the Academy of Sciences: "I was looking for whether there are substances other than uranium compounds that make the wiring for electricity" (Curie, M. 1898). Beginning February 11, 1898, she checked all specimens on hand or borrowed from various collections, including a large number of rocks and minerals. The activity of metallic uranium was taken as a standard. It has been found that these compounds are active and that pitchblende, a massive variety of uraninite from the ores of Joachimsthal in Austria, and chalcolite, natural uranium phosphate, are more active than metallic uranium itself. And a few years later the world found out who discovered radium and polonium.
Marie Curie noted: "This fact is quite remarkable and suggests that these minerals may contain an element much more active than uranium." This artificial chalcolith is not more active than other uranium s alts. At this stage, the hunt for the item became a matter of paramount importance and urgency. Pierre Curie was fascinated by Marie's findings: on March 18, he left his own research projects and joined his wife in studying the subject. Now you know the answer to the question of who discovered the element radium.
During a systematic search for Becquerel rays, Marie Curie also discovered on February 24 that thorium compounds are also active. However, the German physicist GerhardtSchmidt observed the emissions a few weeks ago. Research on uranium rays has now moved from physics to chemistry. It was necessary to separate and identify a substance whose chemical properties are unknown. However, with a hypothetical element, it was possible to monitor its radioactivity. Marie Curie explains this process: “The method we have used is new for chemical studies based on radioactivity. It consists of sections performed with the usual procedures of analytical chemistry and the measurement of the radioactivity of all compounds separated."
Deposition procedures
Thus, it is possible to recognize the chemical nature of the desired radioactive element. Neither Marie nor Pierre were chemists, so they were assisted by Gustave Bemont, who was responsible for the practical training of students at the Paris Municipal School of Physics and Physics. On April 14, the trio conducted research on pitchblende, which was more active than uranium. Several procedures were used in parallel with various precipitations and precipitation of solids, and the active substance was provided mainly with bismuth from which it could gradually separate. On June 27, Marie Curie precipitated sulfides from a solution containing lead, bismuth and the active substance. She highlighted the result in her notebook: the solid was 300 times more active than uranium.
New radioactive substance
July 18, Pierre Curie got a success 400 times more active than with uranium. Curie noted that the compounds of allelements, including the rarest substances, are inactive. On July 18, 1898, Pierre and Marie Curie wrote in the Proceedings of the Academy of Sciences: "We have a new radioactive substance contained in tar." “We believe that the substance that we have extracted from the resin blende contains a previously unknown element, similar to bismuth in its analytical properties. If the existence of this new metal is confirmed, we propose to name it polonium in honor of the motherland” (P. Curie and M. Curie 1998). The public accepted that it was Curie who discovered radium. The Po symbol, written by Pierre Curie, appears in the notebook on 13 July. The name polonium has had a provocative meaning since 1795, being divided among Prussia, Russia and the Austrian Empire.
