Curie and her husband Pierre had convinced the Austrian government which then ruled Bohemia to ship the pitchblende scraps to them in Paris What remained of the mineral was still mixed with dirt and pine needles But Curie didn’t care She knew this mineral also contained treasure The treasure she sought wasn’t gold silver or any other known element She was after something more mysterious She hoped to find an element no one had yet discovered an element some people did not believe was real Uranium Uranium is a metallic silver-white element that was discovered in 1789 by German chemist Martin Klaproth Traditionally elements were named for their discoverer But Klaproth instead decided to name the new element after the newly discovered planet Uranus which was named for the Greek god of the sky Uranium metal tarnishes when exposed to air In powder form it can spontaneously ignite Found largely in central Europe uranium was long used to color ceramics and glassware In 1896 it became the first element in which radioactivity was discovered THE NEED FOR PROOF Less than a year earlier Curie had researched a newly discovered phenomenon which she named radioactivity This term referred to the spontaneous release of energetic rays from certain elements such as uranium and thorium But if Curie’s findings were correct a mysterious new element in pitchblende gave off rays hundreds of times 6
stronger than those of uranium She called the mysterious element radium But radium’s existence was only theoretical To prove it was real Curie had to break down the pitchblende into its component elements This would allow her to isolate enough radium to determine the element’s atomic weight defined as the average mass of one atom of an element Establishing an atomic weight would in turn prove the element was real Curie knew the job wouldn’t be easy but she was determined to prove her theory was correct As she told her sister Bronya The element is there and I’ve got to find it We are sure 1 BACKBREAKING LABOR The facilities for the job were far from ideal Pierre who was also Curie’s research partner taught at Paris’s School of Industrial Physics and Chemistry which was called École Supérieure de Physique et de Chimie Industrielles ESPCI in French The couple had secured the use of an old shed at the school The shed’s uninsulated walls did little against the heat of summer or the cold of winter and rain poured through its leaky skylights onto the dirt floor The room contained a few wooden tables a blackboard and a cast-iron stove well past its prime After visiting the Curies lab German chemist Wilhelm Ostwald described it as a cross between a stable and a potato-cellar 2 7
Pitchblende also known as uraninite is mined in many parts of the world including the United States Although Curie felt disadvantaged by the inadequate facilities she got to work The shed had no vent hoods to carry away poisonous gases so Curie began the first part of her operation outdoors In bad weather she brought everything indoors and opened the windows The first stage of separating the pitchblende involved boiling and melting the ore in a large cauldron Working with 45-pound 8
20 kg batches Curie spent entire days stirring the mixture with an iron rod almost as big as she was She later admitted this work left her broken with fatigue at the day’s end 3 Once the mixture was melted Curie added acids to dissolve the salts in the solution This was followed by more boiling and more chemical treatments filtering pulverizing dissolving and crystallizing until more and more elements had been separated from the pitchblende The various component elements were placed into jars and stored around the lab Gradually Curie produced a substance with greater and greater concentrations of radium As the difficult labor continued Curie hired an assistant Later a factory owner offered to perform the early stages of purification at his facilities Then he would send the resulting product to Curie who still carried out the later more precise stages herself Curie and Pierre had originally estimated that the process of purifying enough material to establish an atomic weight would take a few weeks Instead the Theoretical Interest Not everyone saw the purpose of Curie’s work in isolating radium Even her father Władysław Skłodowska a teacher who first introduced her to a love of physics questioned the effort she put into her discovery In a letter to her he wrote You are now in possession of pure radium salts If we consider the amount of work done in obtaining this it would certainly be the most expensive of chemical elements What a pity it is that this work has only theoretical interest 4 He died six days later never learning how wrong he was 9
