"toxicity is comparable to, but slightly lower than that of americium and plutonium. For trace quantities, fume hoods with good aeration suffice; for gram amounts, hot cells with shielding from the intense gamma radiation emitted by Ac are necessary. Actinium Actinium is a chemical element with symbol Ac and atomic number 89. It was first isolated by French chemist André-Louis Debierne in 1899. Friedrich Oskar Giesel later independently isolated it in 1902 and, unaware that it was already known, gave it the name emanium. Actinium gave the name to the actinide series, a group of 15 similar elements between actinium"
"Actinium Actinium is a chemical element with symbol Ac and atomic number 89. It was first isolated by French chemist André-Louis Debierne in 1899. Friedrich Oskar Giesel later independently isolated it in 1902 and, unaware that it was already known, gave it the name emanium. Actinium gave the name to the actinide series, a group of 15 similar elements between actinium and lawrencium in the periodic table. It is also sometimes considered the first of the 7th-period transition metals, although lawrencium is less commonly given that position. Together with polonium, radium, and radon, actinium was one of the first non-primordial"
"of metals. Cu comes from Cuprum, Fe comes from Ferrum, Ag from Argentum. The symbols were not followed by a period (full stop) as with abbreviations. Later chemical elements were also assigned unique chemical symbols, based on the name of the element, but not necessarily in English. For example, sodium has the chemical symbol 'Na' after the Latin ""natrium"". The same applies to ""W"" (wolfram) for tungsten, ""Fe"" (ferrum) for iron, ""Hg"" (hydrargyrum) for mercury, ""Sn"" (stannum) for tin, ""K"" (kalium) for potassium, ""Au"" (aurum) for gold, ""Ag"" (argentum) for silver, ""Pb"" (plumbum) for lead, ""Cu"" (cuprum) for copper, and"
"Arsenic Arsenic is a chemical element with symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. Arsenic is a metalloid. It has various allotropes, but only the gray form, which has a metallic appearance, is important to industry. The primary use of arsenic is in alloys of lead (for example, in car batteries and ammunition). Arsenic is a common n-type dopant in semiconductor electronic devices, and the optoelectronic compound gallium arsenide is the second most commonly used semiconductor after doped silicon. Arsenic and its"
"sodium acetate, and EtOAc for ethyl acetate. The pseudoelement symbol ""Ac"" is also sometimes encountered in chemical formulas as indicating the entire acetate ion (CHCO), or the acetyl group (CHCO). It is not to be confused with the symbol of actinium, the first element of the actinide series; context guides disambiguation. For example, the formula for sodium acetate might be abbreviated as ""NaAc"", rather than ""NaCHO"". Care should also be taken to avoid confusion with peracetic acid when using the OAc abbreviation; for clarity and to avoid errors when translated, HOAc should be avoided in literature mentioning both compounds. Although"
"also bridged by hydroxo groups) and the aluminium centres subsequently bind to the deprotonated phenol residues of the dye; in the Soubayrol model, each alizarin is associated with a single aluminium cation. As with the structure of aluminium acetate itself, the forms it takes in applications has not been resolved. This ""Ac"" is not referring to the element actinium. Used in this way, the convention in organic chemistry is for Ac to refer to the acetyl group, the radical form of which is , and OAc or AcO would be used for the acetate radical, , sometimes also called ""acetoxy."""
"Acetyl group In organic chemistry, acetyl is a moiety, the acyl with chemical formula CHCO. It is sometimes represented by the symbol Ac (not to be confused with the element actinium). The acetyl group contains a methyl group single-bonded to a carbonyl. The carbonyl center of an acyl radical has one nonbonded electron with which it forms a chemical bond to the remainder ""R"" of the molecule. In IUPAC nomenclature, acetyl is called ethanoyl, although this term is rarely heard. The acetyl moiety is a component of many organic compounds, including acetic acid, the neurotransmitter acetylcholine, acetyl-CoA, acetylcysteine, acetaminophen (also"
"nomenclature. The name ""acetic acid"" derives from ""acetum"", the Latin word for vinegar, and is related to the word acid itself. ""Glacial acetic acid"" is a name for water-free (anhydrous) acetic acid. Similar to the German name ""Eisessig"" (""ice-vinegar""), the name comes from the ice-like crystals that form slightly below room temperature at (the presence of 0.1% water lowers its melting point by 0.2 °C). A common symbol for acetic acid is ""AcOH"", where ""Ac"" is the pseudoelement symbol representing the acetyl group −C(=O)−; the conjugate base, acetate (), is thus represented as ""AcO"". (The ""Ac"" is not to be"
"on heating, force, drying, illumination, or sometimes spontaneously. To avoid the formation of such compounds, ammonia and acetylene should be kept away from silver equipment. Salts of silver with strongly oxidising acids such as silver chlorate and silver nitrate can explode on contact with materials that can be readily oxidised, such as organic compounds, sulfur and soot. Silver Silver is a chemical element with symbol Ag (from the Latin """", derived from the Proto-Indo-European ""h₂erǵ"": ""shiny"" or ""white"") and atomic number 47. A soft, white, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, and reflectivity of any"
"with acetic anhydride yields acetylferrocene just as acylation of benzene yields acetophenone under similar conditions. Iron-centered organometallic species are used as catalysts. The Knölker complex, for example, is a transfer hydrogenation catalyst for ketones. As iron has been in use for such a long time, it has many different names in different languages. The source of its chemical symbol ""Fe"" is the Latin word ""ferrum"", and its descendants are the names of the element in the Romance languages (for example, French ""fer"", Spanish ""hierro"", and Italian and Portuguese ""ferro""). The word ""ferrum"" itself possibly comes from the Semitic languages, via"
"and 2000, arguing that Debierne's publications in 1904 contradicted his earlier work of 1899–1900. This view instead credits the 1902 work of Friedrich Oskar Giesel, who discovered a radioactive element named ""emanium"" that behaved similarly to lanthanum. The name actinium comes from the Greek ""aktis, aktinos"" (ακτίς, ακτίνος), meaning beam or ray. This metal was discovered not by its own radiation but by the radiation of the daughter products. Owing to the close similarity of actinium and lanthanum and low abundance, pure actinium could only be produced in 1950. The term actinide was probably introduced by Victor Goldschmidt in 1937."
"Americium Americium is a synthetic chemical element with symbol Am and atomic number 95. It is radioactive and a transuranic member of the actinide series, in the periodic table located under the lanthanide element europium, and thus by analogy was named after the Americas. Americium was first produced in 1944 by the group of Glenn T. Seaborg from Berkeley, California, at the Metallurgical Laboratory of the University of Chicago, a part of the Manhattan Project. Although it is the third element in the transuranic series, it was discovered fourth, after the heavier curium. The discovery was kept secret and only"
"confused with the symbol for the element actinium; the context prevents confusion among organic chemists.) To better reflect its structure, acetic acid is often written as –C(O)OH, −C(=O)OH, COOH, and . In the context of acid-base reactions, the abbreviation ""HAc"" is sometimes used, where ""Ac"" in this case is a symbol for acetate (rather than acetyl). Acetate is the ion resulting from loss of from acetic acid. The name ""acetate"" can also refer to a salt containing this anion, or an ester of acetic acid. The hydrogen centre in the carboxyl group (−COOH) in carboxylic acids such as acetic acid"
"metals because its fluoride is most volatile. Owing to its scarcity, high price and radioactivity, actinium currently has no significant industrial use. Ac is highly radioactive and was therefore studied for use as an active element of radioisotope thermoelectric generators, for example in spacecraft. The oxide of Ac pressed with beryllium is also an efficient neutron source with the activity exceeding that of the standard americium-beryllium and radium-beryllium pairs. In all those applications, Ac (a beta source) is merely a progenitor which generates alpha-emitting isotopes upon its decay. Beryllium captures alpha particles and emits neutrons owing to its large cross-section"
"Ausonium Ausonium (atomic symbol Ao) was the name assigned to the element with atomic number 93, now known as neptunium. It was named after a Greek name of Italy, Ausonia. The same team assigned the name hesperium to element 94, after Hesperia, a poetic name of Italy. (Element 94 was later named plutonium). The discovery of the element, now discredited, was made by Enrico Fermi and a team of scientists at the University of Rome in 1934. In the same year Ida Noddack had already presented alternative explanations for the experimental results of Fermi. Following the discovery of nuclear fission"
"Silver Silver is a chemical element with symbol Ag (from the Latin """", derived from the Proto-Indo-European ""h₂erǵ"": ""shiny"" or ""white"") and atomic number 47. A soft, white, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, and reflectivity of any metal. The metal is found in the Earth's crust in the pure, free elemental form (""native silver""), as an alloy with gold and other metals, and in minerals such as argentite and chlorargyrite. Most silver is produced as a byproduct of copper, gold, lead, and zinc refining. Silver has long been valued as a precious metal. Silver"
"be colored by anodization are particular advantages. Molybdenum is a Group 6 chemical element with the symbol Mo and atomic number 42. The name is from Neo-Latin ""Molybdaenum"", from Ancient Greek , meaning ""lead"", itself proposed as a loanword from Anatolian Luvian and Lydian languages, since its ores were confused with lead ores. The free element, which is a silvery metal, has the sixth-highest melting point of any element. It readily forms hard, stable carbides, and for this reason it is often used in high-strength steel alloys. Molybdenum does not occur as a free metal on Earth, but rather in"
"Chromium Chromium is a chemical element with symbol Cr and atomic number 24. It is the first element in group 6. It is a steely-grey, lustrous, hard and brittle transition metal. Chromium boasts a high usage rate as a metal that is able to be highly polished while resisting tarnishing. Chromium is also the main component of stainless steel, a popular steel alloy due to its uncommonly high specular reflection. Simple polished chromium reflects almost 70% of the visible spectrum, with almost 90% of infrared light waves being reflected. The name of the element is derived from the Greek word"
"The acetate ion would then be AcO and acetic acid would be AcOH or HOAc. Publications in geochemistry, however, are using Ac to refer to acetate rather than acetyl. Aluminium triacetate Aluminium triacetate, formally named aluminium acetate, is a chemical compound with composition . Under standard conditions it appears as a white, water-soluble solid that decomposes on heating at around 200 °C. The triacetate hydrolyses to a mixture of basic hydroxide / acetate salts, and multiple species co-exist in chemical equilibrium, particularly in aqueous solutions of the acetate ion; the name aluminium acetate is commonly used for this mixed system."
"factories, coal-burning power plants, and metal sewers. The main source of elevated thallium concentrations in water is the leaching of thallium from ore processing operations. Thallium Thallium is a chemical element with symbol Tl and atomic number 81. It is a gray post-transition metal that is not found free in nature. When isolated, thallium resembles tin, but discolors when exposed to air. Chemists William Crookes and Claude-Auguste Lamy discovered thallium independently in 1861, in residues of sulfuric acid production. Both used the newly developed method of flame spectroscopy, in which thallium produces a notable green spectral line. Thallium, from Greek"
"lethal within three weeks; smaller amounts may cause infertility and cancer. The International Atomic Energy Agency and other sources have warned that radioactive materials, such as caesium-137, could be used in radiological dispersion devices, or ""dirty bombs"". Caesium Caesium (IUPAC spelling) or cesium (American spelling) is a chemical element with symbol Cs and atomic number 55. It is a soft, silvery-gold alkali metal with a melting point of 28.5 °C (83.3 °F), which makes it one of only five elemental metals that are liquid at or near room temperature. Caesium has physical and chemical properties similar to those of rubidium"
"Nh and Nh, which have already received preliminary chemical investigations. Roentgenium Roentgenium is a chemical element with symbol Rg and atomic number 111. It is an extremely radioactive synthetic element that can be created in a laboratory but is not found in nature. The most stable known isotope, roentgenium-282, has a half-life of 100 seconds, although the unconfirmed roentgenium-286 may have a longer half-life of about 10.7 minutes. Roentgenium was first created in 1994 by the GSI Helmholtz Centre for Heavy Ion Research near Darmstadt, Germany. It is named after the physicist Wilhelm Röntgen (also spelled Roentgen), who discovered X-rays."
"Actinism Actinism () is the property of solar radiation that leads to the production of photochemical and photobiological effects. ""Actinism"" is derived from the Greek ακτίς, ακτῖνος (a ray or beam). The word ""actinism"" is found, for example, in the terminology of imaging technology (esp. photography), medicine (concerning sunburn), and chemistry (concerning containers that protect from photo-degradation), and the concept of actinism is applied, for example, in chemical photography and X-ray imaging. Actinic () chemicals include silver salts used in photography and other light sensitive chemicals. In chemical terms, actinism is the property of radiation that lets it be absorbed"
"the mineral fluorospar, which was used as a flux in metal working. Chlorine's name comes from the Greek word ""chloros"", meaning ""greenish-yellow"". Bromine's name comes from the Greek word ""bromos"", meaning ""stench"". Iodine's name comes from the Greek word ""iodes"", meaning ""violet"". Astatine's name comes from the Greek word ""astatos"", meaning ""unstable"". Tennessine is named after the US state of Tennessee. The halogens show trends in chemical bond energy moving from top to bottom of the periodic table column with fluorine deviating slightly. (It follows trend in having the highest bond energy in compounds with other atoms, but it has"
"Selenium Selenium is a chemical element with symbol Se and atomic number 34. It is a nonmetal (more rarely considered a metalloid) with properties that are intermediate between the elements above and below in the periodic table, sulfur and tellurium, and also has similarities to arsenic. It rarely occurs in its elemental state or as pure ore compounds in the Earth's crust. Selenium (from Ancient Greek (selḗnē) ""Moon"") was discovered in 1817 by Jöns Jacob Berzelius, who noted the similarity of the new element to the previously discovered tellurium (named for the Earth). Selenium is found in , where it"
"Actinide chemistry Actinide chemistry (or actinoid chemistry) is one of the main branches of nuclear chemistry that investigates the processes and molecular systems of the actinides. The actinides derive their name from the group 3 element actinium. The informal chemical symbol An is used in general discussions of actinide chemistry to refer to any actinide. All but one of the actinides are f-block elements, corresponding to the filling of the 5f electron shell; lawrencium, a d-block element, is also generally considered an actinide. In comparison with the lanthanides, also mostly f-block elements, the actinides show much more variable valence. The"
"Actinide The actinide or actinoid (IUPAC nomenclature) series encompasses the 15 metallic chemical elements with atomic numbers from 89 to 103, actinium through lawrencium. Strictly speaking, both actinium and lawrencium have been labeled as group 3 elements, but both elements are often included in any general discussion of the chemistry of the actinide elements. Actinium is the more often omitted of the two, because its placement as a group 3 element is somewhat more common in texts and for semantic reasons: since ""actinide"" means ""like actinium"", it has been argued that actinium cannot logically be an actinide, even though IUPAC"
"Radium Radium is a chemical element with symbol Ra and atomic number 88. It is the sixth element in group 2 of the periodic table, also known as the alkaline earth metals. Pure radium is silvery-white, but it readily reacts with nitrogen (rather than oxygen) on exposure to air, forming a black surface layer of radium nitride (RaN). All isotopes of radium are highly radioactive, with the most stable isotope being radium-226, which has a half-life of 1600 years and decays into radon gas (specifically the isotope radon-222). When radium decays, ionizing radiation is a product, which can excite fluorescent"
"for example, hydrogen (""water-producing""), oxygen (""acid-producing""), nitrogen (""soda-producing""), bromine (""stink""), and argon (""no reaction"") were based on Greek roots, while the names of iodine and chlorine were derived from the Greek words for their characteristic colors. Indium, rubidium, and thallium were similarly named for the colors of particular lines in their emission spectra. Iridium, which forms compounds of many different colors, takes its name from ""iris"", the Latin for ""rainbow"". The noble gases have all been named for their origin or properties. Helium comes from the Greek ""helios"", meaning ""sun"" because it was first detected as a line in the"
"can regarded as a portmanteau of ""borax"" and ""carbon"". Aluminium was named by Humphry Davy in the early 1800s. It is derived from the Greek word ""alumen"", meaning bitter salt, or the Latin ""alum"", the mineral. Gallium is derived from the Latin ""Gallia"", referring to France, the place of its discovery. Indium comes from the Latin word ""indicum"", meaning indigo dye, and refers to the element's prominent indigo spectroscopic line. Thallium, like indium, is named after the Greek word for the color of its spectroscopic line: ""thallos"", meaning a green twig or shoot. ""Nihonium"" is named after Japan (""Nihon"" in"
"Gallium Gallium is a chemical element with symbol Ga and atomic number 31. It is in group 13 of the periodic table, and thus has similarities to the other metals of the group, aluminium, indium, and thallium. Gallium does not occur as a free element in nature, but as gallium(III) compounds in trace amounts in zinc ores and in bauxite. Elemental gallium is a soft, silvery blue metal at standard temperature and pressure, a brittle solid at low temperatures, and a liquid at temperatures greater than (above room temperature, but below the normal human body temperature of , hence, the"
"in 1938, it was realized that Fermi's discovery was actually a mixture of barium, krypton, and other elements. The actual element was discovered several years later, and assigned the name neptunium. Fascist authorities wanted one of the elements to be named ""littorio"" after the Roman ""lictores"" who carried the ""fasces"", a symbol appropriated by Fascism. Ausonium Ausonium (atomic symbol Ao) was the name assigned to the element with atomic number 93, now known as neptunium. It was named after a Greek name of Italy, Ausonia. The same team assigned the name hesperium to element 94, after Hesperia, a poetic name"
"of 46.612 days. Most of the remaining radioisotopes have half-lives that are less than a day. and are the most often studied NMR-active nuclei, having spins of and respectively. Hg is the modern chemical symbol for mercury. It comes from ""hydrargyrum"", a Latinized form of the Greek word ὑδράργυρος (""hydrargyros""), which is a compound word meaning ""water-silver"" (from ὑδρ- ""hydr-"", the root of ὕδωρ, ""water,"" and ἄργυρος ""argyros"" ""silver"") – since it is liquid like water and shiny like silver. The element was named after the Roman god Mercury, known for his speed and mobility. It is associated with the"