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51-513: The river was polluted with cadmium due to mining at the Kamioka mines (神岡鉱山 Kamioka Kōzan ) and caused the itai-itai disease outbreak in downstream towns that began shortly before World War II . The river passes through or forms the boundary of the following communities: 36°27′42″N 137°14′53″E  /  36.461718°N 137.248153°E  / 36.461718; 137.248153 (mouth) This Gifu Prefecture location article

102-449: A barrier cream on the hands to prevent absorption through the skin even though the amount of cadmium absorbed into the body through the skin is reported to be less than 1%. In PVC , cadmium was used as heat, light, and weathering stabilizers. Currently, cadmium stabilizers have been completely replaced with barium-zinc, calcium-zinc and organo-tin stabilizers. Cadmium is used in many kinds of solder and bearing alloys, because it has

153-416: A self-assembled monolayer one can obtain a cadmium selective electrode with a ppt -level sensitivity. Cadmium has no known function in higher organisms and is considered toxic. Cadmium is considered an environmental pollutant hazardous to living organisms. A cadmium-dependent carbonic anhydrase has been found in some marine diatoms , which live in environments with low zinc concentrations. Cadmium

204-462: A transparent conducting film as early as 1907 by Karl Baedeker . Cadmium oxide in the form of thin films has been used in applications such as photodiodes, phototransistors, photovoltaic cells, transparent electrodes, liquid crystal displays, IR detectors, and anti reflection coatings. CdO microparticles undergo bandgap excitation when exposed to UV-A light and is also selective in phenol photodegradation. Most commercial electroplating of cadmium

255-532: A band gap of 2.18 eV (2.31 eV) at room temperature (298 K). Since cadmium compounds are often found in association with zinc ores, cadmium oxide is a common by-product of zinc refining . It is produced by burning elemental cadmium in air. Pyrolysis of other cadmium compounds, such as the nitrate or the carbonate , also affords this oxide. When pure, it is red, but CdO is unusual in being available in many differing colours due to its tendency to form defect structures resulting from anion vacancies. Cadmium oxide

306-514: A cadmium-bearing mixture of minerals that was named after the Greek mythological character Κάδμος, Cadmus , the founder of Thebes ) was discovered in contaminated zinc compounds sold in pharmacies in Germany in 1817 by Friedrich Stromeyer . Karl Samuel Leberecht Hermann simultaneously investigated the discoloration in zinc oxide and found an impurity, first suspected to be arsenic , because of

357-560: A cadmium-dependent carbonic anhydrase has been found in marine diatoms . Cadmium is a soft, malleable , ductile , silvery-white divalent metal. It is similar in many respects to zinc but forms complex compounds. Unlike most other metals, cadmium is resistant to corrosion and is used as a protective plate on other metals. As a bulk metal, cadmium is insoluble in water and is not flammable ; however, in its powdered form it may burn and release toxic fumes . Although cadmium usually has an oxidation state of +2, it also exists in

408-520: A cigarette is inhaled through smoking. Absorption of cadmium through the lungs is more effective than through the gut. As much as 50% of the cadmium inhaled in cigarette smoke may be absorbed. On average, cadmium concentrations in the blood of smokers is 4 to 5 times greater than non-smokers and in the kidney, 2–3 times greater than in non-smokers. Despite the high cadmium content in cigarette smoke, there seems to be little exposure to cadmium from passive smoking . Cadmium oxide Cadmium oxide

459-499: A common source of blue or ultraviolet laser light. Lasers at wavelengths of 325, 354 and 442 nm are made using this gain medium ; some models can switch between these wavelengths. They are notably used in fluorescence microscopy as well as various laboratory uses requiring laser light at these wavelengths. Cadmium selenide quantum dots emit bright luminescence under UV excitation (He–Cd laser, for example). The color of this luminescence can be green, yellow or red depending on

510-512: A few instances of general population poisoning as the result of long-term exposure to cadmium in contaminated food and water. Research into an estrogen mimicry that may induce breast cancer is ongoing, as of 2012 . In the decades leading up to World War II , mining operations contaminated the Jinzū River in Japan with cadmium and traces of other toxic metals. As a consequence, cadmium accumulated in

561-492: A growing demand for cadmium for nickel–cadmium batteries, which accounted for 81% of the cadmium consumption in the United States in 2006. Cadmium makes up about 0.1  ppm of Earth's crust and is the 65th most abundant element. It is much rarer than zinc, which makes up about 65 ppm. No significant deposits of cadmium-containing ores are known. The only cadmium mineral of importance, greenockite (Cd S ),

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612-560: A half-life of 462.6 days, and Cd with a half-life of 53.46 hours. All of the remaining radioactive isotopes have half-lives of less than 2.5 hours, and the majority have half-lives of less than 5 minutes. Cadmium has 8 known meta states , with the most stable being Cd ( t 1⁄2  = 14.1 years), Cd ( t 1⁄2  = 44.6 days), and Cd ( t 1⁄2  = 3.36 hours). The known isotopes of cadmium range in atomic mass from 94.950  u ( Cd) to 131.946 u ( Cd). For isotopes lighter than 112 u,

663-430: A low coefficient of friction and fatigue resistance. It is also found in some of the lowest-melting alloys , such as Wood's metal . Cadmium is an element in some semiconductor materials. Cadmium sulfide, cadmium selenide, and cadmium telluride are used in some photodetectors and solar cells . HgCdTe detectors are sensitive to mid- infrared light and used in some motion detectors. Helium–cadmium lasers are

714-622: A mixture of cadmium chloride and aluminium chloride , forming the Cd 2 cation, which is similar to the Hg 2 cation in mercury(I) chloride . The structures of many cadmium complexes with nucleobases , amino acids , and vitamins have been determined. Naturally occurring cadmium is composed of eight isotopes . Two of them are radioactive , and three are expected to decay but have not measurably done so under laboratory conditions. The two natural radioactive isotopes are Cd ( beta decay , half-life

765-410: A nominal cell potential of 1.2  V . The cell consists of a positive nickel hydroxide electrode and a negative cadmium electrode plate separated by an alkaline electrolyte ( potassium hydroxide ). The European Union put a limit on cadmium in electronics in 2004 of 0.01%, with some exceptions, and in 2006 reduced the limit on cadmium content to 0.002%. Another type of battery based on cadmium

816-422: A significant correlation between cadmium exposure and occurrence of disease in human populations, a molecular mechanism has not yet been identified. One hypothesis holds that cadmium is an endocrine disruptor and some experimental studies have shown that it can interact with different hormonal signaling pathways. For example, cadmium can bind to the estrogen receptor alpha, and affect signal transduction along

867-400: Is 7.7 × 10  y ) and Cd (two-neutrino double beta decay , half-life is 2.9 × 10  y ). The other three are Cd, Cd (both double electron capture ), and Cd (double beta decay); only lower limits on these half-lives have been determined. At least three isotopes – Cd, Cd, and Cd – are stable. Among the isotopes that do not occur naturally, the most long-lived are Cd with

918-475: Is precipitated from the electrolysis solution. The British Geological Survey reports that in 2001, China was the top producer of cadmium with almost one-sixth of the world's production, closely followed by South Korea and Japan. Cadmium is a common component of electric batteries, pigments , coatings, and electroplating. In 2009, 86% of cadmium was used in batteries , predominantly in rechargeable nickel–cadmium batteries . Nickel–cadmium cells have

969-401: Is a stub . You can help Misplaced Pages by expanding it . This Toyama location article is a stub . You can help Misplaced Pages by expanding it . This article related to a river in Japan is a stub . You can help Misplaced Pages by expanding it . Cadmium Cadmium is a chemical element ; it has symbol Cd and atomic number 48. This soft, silvery-white metal is chemically similar to

1020-431: Is about 0.5 eV, and neutrons below that level are deemed slow neutrons , distinct from intermediate and fast neutrons . Cadmium is created via the s-process in low- to medium-mass stars with masses of 0.6 to 10  solar masses , over thousands of years. In that process, a silver atom captures a neutron and then undergoes beta decay . Cadmium ( Latin cadmia , Greek καδμεία meaning " calamine ",

1071-421: Is an inorganic compound with the formula Cd O. It is one of the main precursors to other cadmium compounds. It crystallizes in a cubic rocksalt lattice like sodium chloride , with octahedral cation and anion centers. It occurs naturally as the rare mineral monteponite. Cadmium oxide can be found as a colorless amorphous powder or as brown or red crystals. Cadmium oxide is an n-type semiconductor with

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1122-443: Is associated with a higher risk of endometrial, breast, and prostate cancer as well as with osteoporosis in humans. A recent study has demonstrated that endometrial tissue is characterized by higher levels of cadmium in current and former smoking females. Cadmium exposure is associated with a large number of illnesses including kidney disease, early atherosclerosis, hypertension, and cardiovascular diseases. Although studies show

1173-482: Is between 0.1 and 0.5 parts per million (ppm). It was discovered in 1817 simultaneously by Stromeyer and Hermann , both in Germany, as an impurity in zinc carbonate . Cadmium occurs as a minor component in most zinc ores and is a byproduct of zinc production. It was used for a long time in the 1900s as a corrosion-resistant plating on steel , and cadmium compounds are used as red, orange, and yellow pigments , to color glass , and to stabilize plastic . Cadmium's use

1224-433: Is done by electrodeposition from cyanide baths. These cyanide baths consist of cadmium oxide and sodium cyanide in water, which likely form cadmium cyanide and sodium hydroxide . A typical formula is 32 g/L cadmium oxide and 75 g/L sodium cyanide. The cadmium concentration may vary by as much as 50%. Brighteners are usually added to the bath and the plating is done at room temperature with high-purity cadmium anodes. CdO

1275-575: Is generally decreasing because it is toxic (it is specifically listed in the European Restriction of Hazardous Substances Directive ) and nickel–cadmium batteries have been replaced with nickel–metal hydride and lithium-ion batteries. Due to it being a neutron poison , cadmium is also used as a component of control rods in nuclear fission reactors. One of its few new uses is in cadmium telluride solar panels . Although cadmium has no known biological function in higher organisms,

1326-602: Is inhalation of fine dust and fumes, or ingestion of highly soluble cadmium compounds. Inhalation of cadmium fumes can result initially in metal fume fever , but may progress to chemical pneumonitis , pulmonary edema , and death. Cadmium is also an environmental hazard. Human exposure is primarily from fossil fuel combustion, phosphate fertilizers, natural sources, iron and steel production, cement production and related activities, nonferrous metals production, and municipal solid waste incineration. Other sources of cadmium include bread, root crops, and vegetables. There have been

1377-499: Is nearly always associated with sphalerite (ZnS). This association is caused by geochemical similarity between zinc and cadmium, with no geological process likely to separate them. Thus, cadmium is produced mainly as a byproduct of mining, smelting, and refining sulfidic ores of zinc, and, to a lesser degree, lead and copper . Small amounts of cadmium, about 10% of consumption, are produced from secondary sources, mainly from dust generated by recycling iron and steel scrap. Production in

1428-545: Is preferentially absorbed in the kidneys of humans. Up to about 30 mg of cadmium is commonly inhaled throughout human childhood and adolescence. Cadmium is under research for its potential toxicity to increase the risk of cancer , cardiovascular disease , and osteoporosis . The biogeochemistry of cadmium and its release to the environment is under research. Individuals and organizations have been reviewing cadmium's bioinorganic aspects for its toxicity. The most dangerous form of occupational exposure to cadmium

1479-407: Is prepared commercially by oxidizing cadmium vapor in air. Cadmium oxide is used in cadmium plating baths, electrodes for storage batteries, cadmium salts, catalysts, ceramic glazes, phosphors, and nematocide. Major uses for cadmium oxide are as an ingredient for electroplating baths, optoelectronic devices, and in pigments. CdO is used as a transparent conductive material, which was prepared as

1530-666: Is the silver–cadmium battery . Cadmium electroplating , consuming 6% of the global production, is used in the aircraft industry to reduce corrosion of steel components. This coating is passivated by chromate salts. A limitation of cadmium plating is hydrogen embrittlement of high-strength steels from the electroplating process. Therefore, steel parts heat-treated to tensile strength above 1300 MPa (200 ksi) should be coated by an alternative method (such as special low-embrittlement cadmium electroplating processes or physical vapor deposition). Titanium embrittlement from cadmium-plated tool residues resulted in banishment of those tools (and

1581-669: The Chinese ministry of agriculture measured that 28% of rice it sampled had excess lead and 10% had excess cadmium above limits defined by law. Consumer Reports tested 28 brands of dark chocolate sold in the United States in 2022, and found cadmium in all of them, with 13 exceeding the California Maximum Allowable Dose level. Some plants such as willow trees and poplars have been found to clean both lead and cadmium from soil. Typical background concentrations of cadmium do not exceed 5 ng/m in

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1632-411: The estrogen and MAPK signaling pathways at low doses. The tobacco plant absorbs and accumulates heavy metals such as cadmium from the surrounding soil into its leaves. Following tobacco smoke inhalation, these are readily absorbed into the body of users. Tobacco smoking is the most important single source of cadmium exposure in the general population. An estimated 10% of the cadmium content of

1683-626: The +1 state. Cadmium and its congeners are not always considered transition metals, in that they do not have partly filled d or f electron shells in the elemental or common oxidation states. Cadmium burns in air to form brown amorphous cadmium oxide (CdO); the crystalline form of this compound is a dark red which changes color when heated, similar to zinc oxide . Hydrochloric acid , sulfuric acid , and nitric acid dissolve cadmium by forming cadmium chloride (CdCl 2 ), cadmium sulfate (CdSO 4 ), or cadmium nitrate (Cd(NO 3 ) 2 ). The oxidation state +1 can be produced by dissolving cadmium in

1734-404: The 1970s, the output of cadmium was 2.9 kilograms (6.5 lb) per ton of zinc. Zinc sulfide ores are roasted in the presence of oxygen , converting the zinc sulfide to the oxide . Zinc metal is produced either by smelting the oxide with carbon or by electrolysis in sulfuric acid . Cadmium is isolated from the zinc metal by vacuum distillation if the zinc is smelted, or cadmium sulfate

1785-641: The United States began in 1907, but wide use began after World War I. Metallic cadmium can be found in the Vilyuy River basin in Siberia . Rocks mined for phosphate fertilizers contain varying amounts of cadmium, resulting in a cadmium concentration of as much as 300 mg/kg in the fertilizers and a high cadmium content in agricultural soils. Coal can contain significant amounts of cadmium, which ends up mostly in coal fly ash . Cadmium in soil can be absorbed by crops such as rice and cocoa. In 2002,

1836-460: The amount of reactivity. The pressurized water reactor designed by Westinghouse Electric Company uses an alloy consisting of 80% silver, 15% indium, and 5% cadmium. QLED TVs have been starting to include cadmium in construction. Some companies have been looking to reduce the environmental impact of human exposure and pollution of the material in televisions during production. Complexes based on cadmium and other heavy metals have potential for

1887-479: The atmosphere; 2 mg/kg in soil; 1 μg/L in freshwater and 50 ng/L in seawater. Concentrations of cadmium above 10 μg/L may be stable in water having low total solute concentrations and p H and can be difficult to remove by conventional water treatment processes. Cadmium is a common impurity in zinc ores, and it is most often isolated during the production of zinc . Some zinc ores concentrates from zinc sulfate ores contain up to 1.4% of cadmium. In

1938-458: The carboxylates cadmium laurate and cadmium stearate on PVC led to an increased use of those compounds in the 1970s and 1980s. The demand for cadmium in pigments, coatings, stabilizers, and alloys declined as a result of environmental and health regulations in the 1980s and 1990s; in 2006, only 7% of total cadmium consumption was used for plating, and only 10% was used for pigments. At the same time, these decreases in consumption were compensated by

1989-530: The implementation of routine tool testing to detect cadmium contamination) in the A-12/SR-71, U-2, and subsequent aircraft programs that use titanium. Cadmium is used in the control rods of nuclear reactors, acting as a very effective neutron poison to control neutron flux in nuclear fission . When cadmium rods are inserted in the core of a nuclear reactor, cadmium absorbs neutrons, preventing them from creating additional fission events, thus controlling

2040-465: The industrial scale production of cadmium started in the 1930s and 1940s, the major application of cadmium was the coating of iron and steel to prevent corrosion; in 1944, 62% and in 1956, 59% of the cadmium in the United States was used for plating . In 1956, 24% of the cadmium in the United States was used for a second application in red, orange and yellow pigments from sulfides and selenides of cadmium. The stabilizing effect of cadmium chemicals like

2091-487: The most common. Cadmium selenide is a red pigment, commonly called cadmium red . To painters who work with the pigment, cadmium provides the most brilliant and durable yellows, oranges, and reds – so much so that during production, these colors are significantly toned down before they are ground with oils and binders or blended into watercolors , gouaches , acrylics , and other paint and pigment formulations. Because these pigments are potentially toxic, users should use

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2142-596: The particle size. Colloidal solutions of those particles are used for imaging of biological tissues and solutions with a fluorescence microscope . In molecular biology, cadmium is used to block voltage-dependent calcium channels from fluxing calcium ions, as well as in hypoxia research to stimulate proteasome -dependent degradation of Hif-1α . Cadmium-selective sensors based on the fluorophore BODIPY have been developed for imaging and sensing of cadmium in cells. One powerful method for monitoring cadmium in aqueous environments involves electrochemistry . By employing

2193-444: The primary decay mode is electron capture and the dominant decay product is element 47 ( silver ). Heavier isotopes decay mostly through beta emission producing element 49 ( indium ). One isotope of cadmium, Cd, absorbs neutrons with high selectivity: With very high probability, neutrons with energy below the cadmium cut-off will be absorbed; those higher than the cut-off will be transmitted . The cadmium cut-off

2244-436: The rice crops along the riverbanks downstream of the mines. Some members of the local agricultural communities consumed the contaminated rice and developed itai-itai disease and renal abnormalities, including proteinuria and glucosuria . The victims of this poisoning were almost exclusively post-menopausal women with low iron and low body stores of other minerals. Similar general population cadmium exposures in other parts of

2295-406: The scope of the law. The International Agency for Research on Cancer has classified cadmium and cadmium compounds as carcinogenic to humans. Although occupational exposure to cadmium is linked to lung and prostate cancer, there is still uncertainty about the carcinogenicity of cadmium in low environmental exposure. Recent data from epidemiological studies suggest that intake of cadmium through diet

2346-408: The treatment of cancer, but their use is often limited due to toxic side effects. Cadmium oxide was used in black and white television phosphors and in the blue and green phosphors of color television cathode ray tubes. Cadmium sulfide (CdS) is used as a photoconductive surface coating for photocopier drums. Various cadmium salts are used in paint pigments, with CdS as a yellow pigment being

2397-543: The two other stable metals in group 12 , zinc and mercury . Like zinc, it demonstrates oxidation state +2 in most of its compounds, and like mercury, it has a lower melting point than the transition metals in groups 3 through 11 . Cadmium and its congeners in group 12 are often not considered transition metals, in that they do not have partly filled d or f electron shells in the elemental or common oxidation states. The average concentration of cadmium in Earth's crust

2448-594: The world have not resulted in the same health problems because the populations maintained sufficient iron and other mineral levels. Thus, although cadmium is a major factor in the itai-itai disease in Japan, most researchers have concluded that it was one of several factors. Cadmium is one of ten substances banned by the European Union's Restriction of Hazardous Substances (RoHS) directive, which regulates hazardous substances in electrical and electronic equipment, but allows for certain exemptions and exclusions from

2499-556: The yellow precipitate with hydrogen sulfide . Additionally Stromeyer discovered that one supplier sold zinc carbonate instead of zinc oxide. Stromeyer found the new element as an impurity in zinc carbonate (calamine), and, for 100 years, Germany remained the only important producer of the metal. The metal was named after the Latin word for calamine, because it was found in this zinc ore. Stromeyer noted that some impure samples of calamine changed color when heated but pure calamine did not. He

2550-488: Was persistent in studying these results and eventually isolated cadmium metal by roasting and reducing the sulfide . The potential for cadmium yellow as pigment was recognized in the 1840s, but the lack of cadmium limited this application. Even though cadmium and its compounds are toxic in certain forms and concentrations, the British Pharmaceutical Codex from 1907 states that cadmium iodide

2601-522: Was used as a medication to treat "enlarged joints, scrofulous glands, and chilblains". In 1907, the International Astronomical Union defined the international ångström in terms of a red cadmium spectral line (1 wavelength = 6438.46963 Å). This was adopted by the 7th General Conference on Weights and Measures in 1927. In 1960, the definitions of both the metre and ångström were changed to use krypton . After

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