Radium bromide is the bromide

salt In common usage, salt is a mineral composed primarily of sodium chloride (NaCl). When used in food, especially in granulated form, it is more formally called table salt. In the form of a natural crystalline mineral, salt is also known as r ...

radium Radium is a chemical element; it has chemical symbol, symbol Ra and atomic number 88. It is the sixth element in alkaline earth metal, group 2 of the periodic table, also known as the alkaline earth metals. Pure radium is silvery-white, ...

, with the formula RaBr₂. It is produced during the process of separating radium from

uranium Uranium is a chemical element; it has chemical symbol, symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Ura ...

ore. This inorganic compound was discovered by Pierre and

Marie Curie Maria Salomea Skłodowska-Curie (; ; 7 November 1867 – 4 July 1934), known simply as Marie Curie ( ; ), was a Polish and naturalised-French physicist and chemist who conducted pioneering research on radioactivity. She was List of female ...

in 1898, and the discovery sparked a huge interest in radiochemistry and

radiotherapy Radiation therapy or radiotherapy (RT, RTx, or XRT) is a treatment using ionizing radiation, generally provided as part of cancer therapy to either kill or control the growth of malignant cells. It is normally delivered by a linear particle ...

. Since elemental radium oxidizes readily in air and water, radium salts are the preferred chemical form of radium to work with.Babcock, A.B., Jr. Survey of Processes for Radium Recovery from Pitchblende Ores. ''AEC Research and Development Report''. 23 Feb 1950. No. NYO—112 Even though it is more stable than elemental radium, radium bromide is still extremely toxic, and can explode under certain conditions.Kirby, H.W; Salutsky, Murrell L. The Radiochemistry of Radium. ''Energy Citations Database'' Dec 1964''

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History

After the Curies discovered radium (in the form of radium chloride) in 1898, scientists began to isolate radium on an industrial scale, with the intent of using it for

treatments. Radium salts, including radium bromide, were most often used by placing the chemical in a tube that was then passed over or inserted into diseased tissue in the body. Many of the first scientists to try to determine radium's uses were affected by their exposure to the radioactive material. Pierre Curie went so far as to self-inflict a severe chemical skin reaction by applying a radium source directly to his forearm, which ultimately created a skin lesion.Dutreix, Jean; Pierquin, Bernard; Tubiana, Maurice. The Hazy Dawn of Brachytherapy. ''Radiotherapy and Oncology'' (49) 1998 223-232 All types of therapeutic tests were performed for different skin diseases including

eczema Dermatitis is a term used for different types of skin inflammation, typically characterized by itchiness, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become thickened ...

lichen A lichen ( , ) is a hybrid colony (biology), colony of algae or cyanobacteria living symbiotically among hypha, filaments of multiple fungus species, along with yeasts and bacteria embedded in the cortex or "skin", in a mutualism (biology), m ...

and

psoriasis Psoriasis is a long-lasting, noncontagious autoimmune disease characterized by patches of abnormal skin. These areas are red, pink, or purple, dry, itchy, and scaly. Psoriasis varies in severity from small localized patches to complete b ...

. Later, it was hypothesized that radium could be used to treat cancerous diseases. However, during this time frame, radium also gained popularity among pseudoscientific "health remedy" industries, which promoted radium as an essential element that could "heal" and "reinvigorate" cells in the human body and remove poisonous substances. As a result, radium gained popularity as a "health trend" in the 1920s and radium salts were added to food, drinks, clothing, toys, and even toothpaste.Harvie, David I. The Radium Century. ''Endeavor'' 1999 Vol. 23, Issue 3: 100-105 Furthermore, many respectable journals and newspapers in the early 1900s published statements claiming that radium posed no health hazard. The main problem with the growth of interest in radium was the lack of radium on earth itself. In 1913, it was reported that the Radium Institute had four grams of radium total, which at the time was more than half the world supply. Numerous countries and institutions across the world set out to extract as much radium as possible, a time-consuming and expensive task. It was reported in ''Science'' magazine in 1919 that the United States had produced approximately 55 grams of radium since 1913, which was also more than half the radium produced in the world at the time.Voil, Charles H. Radium Production. ''Science'' 17 March 1919 Vol. 49, No 1262: 227-228 A principal source for radium is

pitchblende Uraninite, also known as pitchblende, is a radioactive, uranium-rich mineral and ore with a chemical composition that is largely UO2 but because of oxidation typically contains variable proportions of U3O8. Radioactive decay of the urani ...

, which holds a total of 257 mg of radium per ton of U₃O₈. With so little product recovered from such a large amount of material, it was difficult to extract a large quantity of radium. This was the reason radium bromide became one of the most expensive materials on earth. In 1921, it was stated in ''Time'' magazine that one ton of radium cost 17,000,000,000 Euros, whereas one ton of gold cost 208,000 Euros and one ton of diamond cost 400,000,000 Euros. Radium bromide was also found to induce

phosphorescence Phosphorescence is a type of photoluminescence related to fluorescence. When exposed to light (radiation) of a shorter wavelength, a phosphorescent substance will glow, absorbing the light and reemitting it at a longer wavelength. Unlike fluor ...

at normal temperatures.100 and 50 years ago. ''Nature'' 24 July 2003 Vol. 424, Issue 6927: 381 This led to the US army manufacturing and supplying luminous watches and gun sights to soldiers. It also allowed for the invention of the

spinthariscope A spinthariscope () is a device for observing individual Radioactive decay, nuclear disintegrations caused by the interaction of ionizing radiation with a phosphor (see radioluminescence) or scintillator. Invention The spinthariscope was invente ...

, which soon became a popular household item.Schwarcz, Joe. A Dazzling display in a little jar. ''The Gazette: Saturday Extra; The Right Chemistry'' pg B5

Properties

Radium bromide is a luminous salt that causes the air surrounding it, even when encased in a tube, to glow a brilliant green and demonstrate all bands of the nitrogen spectrum. It is possible that the effect of the

alpha radiation Alpha decay or α-decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle (helium nucleus). The parent nucleus transforms or "decays" into a daughter product, with a mass number that is reduced by four and an atom ...

on the

nitrogen Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...

in the air causes this

luminescence Luminescence is a spontaneous emission of radiation from an electronically or vibrationally excited species not in thermal equilibrium with its environment. A luminescent object emits ''cold light'' in contrast to incandescence, where an obje ...

. Radium bromide is highly reactive and crystals can sometimes explode, especially if heated. Helium gas evolved from alpha particles can accumulate within the crystals, which can cause them to weaken and rupture. Radium bromide will crystallize when separated from aqueous solution. It forms a dihydrate, very similar to barium bromide.

Production

Radium is obtained from uranium or

ores by the "Curie method", which involves two major stages. In the first stage the ore is treated with sulfuric acid dissolves many components. The residue contains, barium, radium, and lead sulfates. The mixture will then be treated with

sodium chloride Sodium chloride , commonly known as Salt#Edible salt, edible salt, is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. It is transparent or translucent, brittle, hygroscopic, and occurs a ...

and sodium carbonate to remove the lead. The second stage involves separation of the barium from the radium. Radium bromide can be obtained from radium chloride by reaction with a stream of

hydrogen bromide Hydrogen bromide is the inorganic compound with the formula . It is a hydrogen halide consisting of hydrogen and bromine. A colorless gas, it dissolves in water, forming hydrobromic acid, which is saturated at 68.85% HBr by weight at room temper ...

Hazards

Radium bromide, like all radium compounds, is highly radioactive and very toxic. Due to its chemical similarity to

calcium Calcium is a chemical element; it has symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to it ...

, radium tends to accumulate in the bones, where it irradiates the

bone marrow Bone marrow is a semi-solid biological tissue, tissue found within the Spongy bone, spongy (also known as cancellous) portions of bones. In birds and mammals, bone marrow is the primary site of new blood cell production (or haematopoiesis). It i ...

and can cause

anemia Anemia (also spelt anaemia in British English) is a blood disorder in which the blood has a reduced ability to carry oxygen. This can be due to a lower than normal number of red blood cells, a reduction in the amount of hemoglobin availabl ...

leukemia Leukemia ( also spelled leukaemia; pronounced ) is a group of blood cancers that usually begin in the bone marrow and produce high numbers of abnormal blood cells. These blood cells are not fully developed and are called ''blasts'' or '' ...

sarcoma A sarcoma is a rare type of cancer that arises from cells of mesenchymal origin. Originating from mesenchymal cells means that sarcomas are cancers of connective tissues such as bone, cartilage, muscle, fat, or vascular tissues. Sarcom ...

bone cancer A bone tumor is an neoplastic, abnormal growth of tissue in bone, traditionally classified as benign, noncancerous (benign) or malignant, cancerous (malignant). Cancerous bone tumors usually originate from a cancer in another part of the body su ...

, genetic defects,

infertility In biology, infertility is the inability of a male and female organism to Sexual reproduction, reproduce. It is usually not the natural state of a healthy organism that has reached sexual maturity, so children who have not undergone puberty, whi ...

, ulcers, and

necrosis Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. The term "necrosis" came about in the mid-19th century and is commonly attributed to German pathologist Rudolf Virchow, who i ...

. Symptoms of poisoning can take years to develop, by which time it is usually too late for any effective medical treatment. Radium bromide also poses a severe

environmental hazard Environmental hazards are hazards that affect biomes or ecosystems. Well known examples include oil spills, water pollution, slash and burn deforestation, air pollution, ground fissures, and Carbon dioxide in Earth's atmosphere, build-up of atmosp ...

, amplified due to its high

solubility In chemistry, solubility is the ability of a chemical substance, substance, the solute, to form a solution (chemistry), solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form su ...

in water, and it can bioaccumulate and cause long-lasting damage to organisms. Radium bromide is highly reactive, and crystals can explode if violently shocked or heated. This is, in part, due to self-damage of the crystals by alpha radiation, which weakens the lattice structure.

Uses

Radium and radium salts were commonly used for treating

cancer Cancer is a group of diseases involving Cell growth#Disorders, abnormal cell growth with the potential to Invasion (cancer), invade or Metastasis, spread to other parts of the body. These contrast with benign tumors, which do not spread. Po ...

; however, these treatments have been mostly phased out in favor of less toxic chemicals such as

technetium Technetium is a chemical element; it has Symbol (chemistry), symbol Tc and atomic number 43. It is the lightest element whose isotopes are all radioactive. Technetium and promethium are the only radioactive elements whose neighbours in the sense ...

or strontium-89. Radium bromide was also used in luminous paint on watches, but its use was ultimately phased out in the 1960-1970s in favor of less dangerous chemicals like

promethium Promethium is a chemical element; it has Symbol (chemistry), symbol Pm and atomic number 61. All of its isotopes are Radioactive decay, radioactive; it is extremely rare, with only about 500–600 grams naturally occurring in the Earth's crust a ...

and

tritium Tritium () or hydrogen-3 (symbol T or H) is a rare and radioactive isotope of hydrogen with a half-life of ~12.33 years. The tritium nucleus (t, sometimes called a ''triton'') contains one proton and two neutrons, whereas the nucleus of the ...

References