銥
Iridium

context: zh_tw: 銥的氧化態介於−3 和 + 9 間，最常見的氧化態為 + 3 和 + 4。高氧化態的化合物比較罕見，包括 IrF6 和兩種混合氧化物 Sr2MgIrO6 及 Sr2CaIrO6。2009 年，科學家利用基質隔離方法（在 6 K 的氬氣中）對過氧化銥配合物進行紫外線照射，製成了四氧化銥（IrO4）。然而這一化合物預計在更高的溫度下無法穩定保持固體狀態。銥的最高氧化態為 + 9，是所有已知元素中最高的，只存在於 IrO+4，它以氣態形式出現，未知是否會形成任何鹽。二氧化銥（IrO2）為棕色粉末，是銥唯一一種性質已經過充分研究的氧化物。三氧化二銥是一種黑藍色粉末，在硝酸中會氧化成 IrO2。其他已知的化合物包括二硫化銥、二硒化銥、三硫化二銥和三硒化二銥等，另外也有研究指出 IrS3 的存在。銥還可以形成氧化態為 + 4 和 + 5 的銥酸，如 K2IrO3 和 KIrO3。在高溫下使銥與氧化鉀或超氧化鉀反應，就可取得這些銥酸。目前尚未發現化學式為 IrxHy 的氫銥二元化合物，但有些已知配合物包含 IrH4−5 和 IrH3−6 離子，其中銥的氧化態分別為 + 1 和 + 3。科學家認為，Mg6Ir2H11 當中同時存在 IrH4−5 以及含 18 個電子的 IrH5−4 離子。銥並不形成一鹵化物和二鹵化物，而是會與每一種鹵素形成對應的三鹵化物 IrX3。氧化態為 + 4 或以上的鹵化物只有四氟化銥、五氟化銥和六氟化銥。六氟化銥（IrF6）是一種反應性很高的揮發性黃色固體，其分子結構呈八面體形。它在水中會分解，而且銥黑（即金屬銥粉末）可將其還原成晶體狀的四氟化銥（IrF4）。五氟化銥的特性相似，但它其實是一種四聚體 Ir4F20，由四個角對角連線的八面體所形成。
en: Iridium forms compounds in oxidation states between −3 and +9; the most common oxidation states are +3 and +4. Well-characterized examples of the high +6 oxidation state are rare, but include IrF6 and two mixed oxides Sr2MgIrO6 and Sr2CaIrO6. In addition, it was reported in 2009 that iridium(VIII) oxide (IrO4) was prepared under matrix isolation conditions (6 K in Ar) by UV irradiation of an iridium-peroxo complex. This species, however, is not expected to be stable as a bulk solid at higher temperatures. The highest oxidation state (+9), which is also the highest recorded for any element, is only known in one cation, IrO+4; it is only known as gas-phase species and is not known to form any salts.Iridium dioxide, IrO2, a blue black solid, is the only well-characterized oxide of iridium. A sesquioxide, Ir2O3, has been described as a blue-black powder which is oxidized to IrO2 by HNO3. The corresponding disulfides, diselenides, sesquisulfides, and sesquiselenides are known, and IrS3 has also been reported. Iridium also forms iridates with oxidation states +4 and +5, such as K2IrO3 and KIrO3, which can be prepared from the reaction of potassium oxide or potassium superoxide with iridium at high temperatures.Although no binary hydrides of iridium, IrxHy are known, complexes are known that contain IrH4−5 and IrH3−6, where iridium has the +1 and +3 oxidation states, respectively. The ternary hydride Mg6Ir2H11 is believed to contain both the IrH4−5 and the 18-electron IrH5−4 anion.No monohalides or dihalides are known, whereas trihalides, IrX3, are known for all of the halogens. For oxidation states +4 and above, only the tetrafluoride, pentafluoride and hexafluoride are known. Iridium hexafluoride, IrF6, is a volatile and highly reactive yellow solid, composed of octahedral molecules. It decomposes in water and is reduced to IrF4, a crystalline solid, by iridium black. Iridium pentafluoride has similar properties but it is actually a tetramer, Ir4F20, formed by four corner-sharing octahedra. Iridium metal dissolves in molten alkali-metal cyanides to produce the Ir(CN)3+6 (hexacyanoiridate) ion.
qas: question: zh_tw: 三元氫化物 Mg6Ir2H11 被認為包含哪些電子？
en: What are the electrons that the ternary hydride Mg6lr2H11 are believed to contain?
answers: zh_tw: text: IrH4−5 以及含 18 個電子的 IrH5−4 離子
en: text: the IrH4−5 and the 18-electron IrH5−4 anion

context: zh_tw: 銥有兩種自然穩定同位素：191Ir 和 193Ir，丰度分別為 37.3% 和 62.7%。已人工合成的放射性同位素共有 34 種，質量數從 164 至 199 不等。192Ir 夾在兩個穩定同位素之間，也是最穩定的放射性同位素，半衰期為 73.827 天。這一同位素在近距離治療和工業射線照相技術中具有用途，特別是在天然氣工業中用於無損檢測鋼鐵的焊接處。銥 - 192 曾造成多宗輻射意外。另外有三個同位素的半衰期在一天以上：188Ir、189Ir 和 190Ir。質量數低於 191 的同位素會同時進行 β+ 衰變、α 衰變以及質子發射，但有兩者除外：189Ir 進行電子捕獲，而 190Ir 進行正電子發射。質量數高於 191 的同位素則進行 β−衰變，其中 192Ir 會少量進行電子捕獲。所有銥同位素都是在 1934 至 2001 年間發現的，其中最新發現的是 171Ir。銥共有 32 種已知同核異構體，質量數介乎 164 到 197。最穩定的同核異構體是 192m2Ir，它會經同核異能躍遷，半衰期為 241 年，因此比所有處於基態的放射性同位素都要穩定。最不穩定的異構體是 190m3Ir，其半衰期只有 2 微秒。191Ir 是所有元素中首個被證實呈現穆斯堡爾效應的同位素。該同位素應用在穆斯堡爾光譜分析中，在物理學、化學、生物化學、冶金學和礦物學等領域都有用到。
en: Iridium has two naturally occurring, stable isotopes, 191Ir and 193Ir, with natural abundances of 37.3% and 62.7%, respectively. At least 37 radioisotopes have also been synthesized, ranging in mass number from 164 to 202. 192Ir, which falls between the two stable isotopes, is the most stable radioisotope, with a half-life of 73.827 days, and finds application in brachytherapy and in industrial radiography, particularly for nondestructive testing of welds in steel in the oil and gas industries; iridium-192 sources have been involved in a number of radiological accidents. Three other isotopes have half-lives of at least a day—188Ir, 189Ir, and 190Ir. Isotopes with masses below 191 decay by some combination of β+ decay, α decay, and (rare) proton emission, with the exceptions of 189Ir, which decays by electron capture. Synthetic isotopes heavier than 191 decay by β− decay, although 192Ir also has a minor electron capture decay path. All known isotopes of iridium were discovered between 1934 and 2008, with the most recent discoveries being 200-202Ir.At least 32 metastable isomers have been characterized, ranging in mass number from 164 to 197. The most stable of these is 192m2Ir, which decays by isomeric transition with a half-life of 241 years, making it more stable than any of iridium's synthetic isotopes in their ground states. The least stable isomer is 190m3Ir with a half-life of only 2 µs. The isotope 191Ir was the first one of any element to be shown to present a Mössbauer effect. This renders it useful for Mössbauer spectroscopy for research in physics, chemistry, biochemistry, metallurgy, and mineralogy.
qas: question: zh_tw: 銥在自然界中有幾種穩定同位素？
en: How many stable isotopes does iridium have in nature?
answers: zh_tw: text: 兩種
en: text: two

context: zh_tw: 銥是鎳和銅開採和提煉過程的副產品。在鎳和銅的電解精煉過程中，金、銀等貴金屬、鉑系元素以及硒和碲等非金屬元素都會積聚在正電極上。這一泥狀物質要進入溶液才可把其中的金屬分離出來。具體方法取決於混合物的成份，但主要有兩種：加入過氧化鈉後溶於王水，或直接溶於氯和氫氯酸的混合溶液。要在溶解狀態下從其他鉑系金屬中分離出銥，需使 (NH4) 2IrCl6 沉澱，或用有機胺把 IrCl2−6 萃取出來。第一種分離方法類似於特南特所用的方法。第二種方法可以作為持續的溶劑提取過程，所以更適合工業規模的生產。兩種方法的產物都可用氫進行還原反應，產生粉末或海綿狀的銥金屬，再用粉末冶金技術來加工。過去數十年間的銥價格波動頗大。相對其他工業用金屬（如鋁和銅）來說，銥的全球市場量很小，所以價格很容易受產量、需求量、投機、囤積和產國政治等多方面變化的影響。由於屬性特殊，所以銥的價格會隨當今科技的變化而波動：用來製造大型單個晶體的銥制坩堝滯銷，導致銥價格在 2001 至 2003 年間下降。2010 至 2014 年，多個生產單個藍寶石晶體的工廠建立，促使銥價升至超過每盎司 1000 美元。這些藍寶石被用於電視 LED 背光燈中。
en: Iridium is also obtained commercially as a by-product from nickel and copper mining and processing. During electrorefining of copper and nickel, noble metals such as silver, gold and the platinum group metals as well as selenium and tellurium settle to the bottom of the cell as anode mud, which forms the starting point for their extraction. To separate the metals, they must first be brought into solution. Several separation methods are available depending on the nature of the mixture; two representative methods are fusion with sodium peroxide followed by dissolution in aqua regia, and dissolution in a mixture of chlorine with hydrochloric acid.After the mixture is dissolved, iridium is separated from the other platinum group metals by precipitating ammonium hexachloroiridate ((NH4)2IrCl6) or by extracting IrCl2−6 with organic amines. The first method is similar to the procedure Tennant and Wollaston used for their separation. The second method can be planned as continuous liquid–liquid extraction and is therefore more suitable for industrial scale production. In either case, the product is reduced using hydrogen, yielding the metal as a powder or sponge that can be treated using powder metallurgy techniques.Iridium prices have fluctuated over a considerable range. With a relatively small volume in the world market (compared to other industrial metals like aluminium or copper), the iridium price reacts strongly to instabilities in production, demand, speculation, hoarding, and politics in the producing countries.
qas: question: zh_tw: 分離金屬的第一步是什麼？
en: What is the first step to separating the metals?
answers: zh_tw: text: 進入溶液
en: text: brought into solution

context: zh_tw: 1889 年製成的國際米原器和國際公斤原器是由含 90% 鉑和 10% 銥的合金組成的，原器由位於巴黎附近的國際度量衡局儲存。米的定義在 1960 年改為氪的發射光譜中的一條譜線，但千克的定義仍然是千克原器（至 2019 年 5 月 20 日）。航海家號、維京號、先鋒號和卡西尼－惠更斯號、伽利略號和新視野號等無人宇宙飛船都有使用含有銥的放射性同位素熱電機。由於熱電機要承受高達 2000 °C 的高溫，所以包裹著鈽 - 238 同位素的容器是以既堅硬又耐高溫的銥所制。銥還被用於 X 射線望遠鏡中。錢德拉 X 射線天文臺的反射鏡上有一層 60 奈米厚的銥塗層。在測試過多種金屬之後，銥的 X 射線反射能力證明比鎳、金和鉑都要優勝。這層銥的平滑程度要有幾個原子以內的準確度，須在氣態下在高真空環境中塗在鉻底層上。粒子物理學在反質子的產生過程中也用到銥。過程中，高強度質子束射向密度必須很高的「轉換目標體」。雖然可以使用鎢，但銥的優勝之處在於，它可以更穩定地承受入射粒子束使溫度升高時所造成的衝擊波。
en: While other metals can be used for coating objects for SEM use, Iridium is the preferred coating when samples will be studied with a wide variety of imaging parameters.Iridium has been used in the radioisotope thermoelectric generators of unmanned spacecraft such as the Voyager, Viking, Pioneer, Cassini, Galileo, and New Horizons. Iridium was chosen to encapsulate the plutonium-238 fuel in the generator because it can withstand the operating temperatures of up to 2000 °C and for its great strength.Another use concerns X-ray optics, especially X-ray telescopes. The mirrors of the Chandra X-ray Observatory are coated with a layer of iridium 60 nm thick. Iridium proved to be the best choice for reflecting X-rays after nickel, gold, and platinum were also tested. The iridium layer, which had to be smooth to within a few atoms, was applied by depositing iridium vapor under high vacuum on a base layer of chromium.Iridium is used in particle physics for the production of antiprotons, a form of antimatter. Antiprotons are made by shooting a high-intensity proton beam at a conversion target, which needs to be made from a very high density material. Although tungsten may be used instead, iridium has the advantage of better stability under the shock waves induced by the temperature rise due to the incident beam.
qas: question: zh_tw: 錢德拉 X 射線天文臺的反射鏡的銥塗層有多厚？
en: How thick is the layered coating of iridium on the Chandra X-ray Observatory mirrors?
answers: zh_tw: text: 60 奈米
en: text: 60 nm