Question: What chemical compound did the first woman to win a nobel prize use to separate radium from barium?
Context: Europium barium titanate is a chemical compound composed of barium, europium, titanium, and oxygen.  It is magnetic and ferroelectric. Frankdicksonite is a halide mineral with the chemical formula BaF which corresponds to the chemical compound barium fluoride.  It occurs in the Carlin gold deposit of Eureka County, Nevada as cubic crystals sized between 0.1 and 4 mm, and is of hydrothermal origin.  Its only associated mineral is quartz and the frankdicksonite crystals are always completely encapsulated in it.  Frankdicksonite has fluorite crystal structure with a cubic symmetry and the lattice constant "a" = 619.64 pm.  Its Vickers hardness on the {111} cleavage crystal faces varies between 88 and 94 kg/mm and is close to that of the synthetic barium fluoride (95 kg/mm).  Its refractive index (1.475) is almost identical to that of BaF (1.474).  Under electron irradiation, it emits strong blue cathodoluminescence.  The major impurity in frankdicksonite is strontium with concentrations up to 0.5% by weight.  Also present are silicon (0.02%) and magnesium (0.0015%); other impurities have concentrations below 0.0015%. Barium cyanide is a chemical compound with the formula Ba(CN).  It is synthesized by the reaction of hydrogen cyanide and barium hydroxide in water or petroleum ether.  This white crystal reacts with water and carbon dioxide in air slowly, producing highly toxic hydrogen cyanide gas. Radium chloride (RaCl) is a chemical compound of radium and chlorine, and the first radium compound isolated in a pure state.  Marie Curie and André-Louis Debierne used it in their original separation of radium from barium.  The first preparation of radium metal was by the electrolysis of a solution of this salt using a mercury cathode. Barium fluoride (BaF) is a chemical compound of barium and fluorine and is a salt.  It is a solid which can be a transparent crystal.  It occurs in nature as the mineral frankdicksonite. Barium ferrate is the chemical compound of formula BaFeO.  This is a rare compound containing iron in the +6 oxidation state.  The ferrate (VI) ion has two unpaired electrons, making it paramagnetic.  It is isostructural with BaSO, and contains the tetrahedral <nowiki>[</nowiki>FeO<nowiki>]</nowiki> anion. Barium bromide is the chemical compound with the formula BaBr.  Like barium chloride, it dissolves well in water and is toxic in aqueous solution. Ada E. Yonath (Hebrew: עדה יונת‎ ‎ , ] ) (born 22 June 1939) is an Israeli crystallographer best known for her pioneering work on the structure of the ribosome.  She is the current director of the Helen and Milton A. Kimmelman Center for Biomolecular Structure and Assembly of the Weizmann Institute of Science.  In 2009, she received the Nobel Prize in Chemistry along with Venkatraman Ramakrishnan and Thomas A. Steitz for her studies on the structure and function of the ribosome, becoming the first Israeli woman to win the Nobel Prize out of ten Israeli Nobel laureates, the first woman from the Middle East to win a Nobel prize in the sciences, and the first woman in 45 years to win the Nobel Prize for Chemistry.  However, she said herself that there was nothing special about a woman winning the Prize. Pangamic acid, also called pangamate, is the name given to the chemical compound described as "-gluconodimethylamino acetic acid", initially promoted by Ernst T. Krebs, Sr. and his son Ernst T. Krebs, Jr. as a medicinal compound for use in treatment of a wide range of diseases.  They also termed this chemical "Vitamin B", though it is not a true vitamin, has no nutritional value, has no known use in the treatment of any disease and has been called a "quack remedy".  Although a number of compounds labelled "pangamic acid" have been studied or sold, no chemical compound, including those claimed by the Krebses to be pangamic acid, has been scientifically verified to have the characteristics that defined the original description of the compound. Marie Skłodowska Curie ( ; ] ; ] ; 7 November 18674 July 1934; born Maria Salomea Skłodowska; ] ) 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 only woman to win twice, the only person to win a Nobel Prize in two different sciences, and 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.
Answer: Radium chloride