"Anzaite-(Ce) Anzaite-(Ce) is a rare-earth element (REE) oxide mineral with the formula CeFeTiO(OH). An example of chemically related mineral is lucasite-(Ce), although it contains no iron. Cerium in anzaite-(Ce) is mainly substituted by neodymium, lanthanum, calcium and praseodymium. Titanium is substituted by niobium. Trace elements include thorium. The mineral is monoclinic, space group ""C""2/""m"". Anzaite-(Ce) is hydrothermal mineral found in a carbonatite from the mineralogically-prolific Kola Peninsula. The mineral name honors Anatoly N. Zaitsev, who is known for studies of carbonatites and REE. Parent rocks for anzaite-(Ce) are silicocarbonatites of the Afrikanda alkali-ultramafic massif. These rocks underwent hydrothermal reworking, that"
"cell membranes, but this is not an important risk because it is not very soluble in water. Cerium Cerium is a chemical element with symbol Ce and atomic number 58. Cerium is a soft, ductile and silvery-white metal that tarnishes when exposed to air, and it is soft enough to be cut with a knife. Cerium is the second element in the lanthanide series, and while it often shows the +3 oxidation state characteristic of the series, it also exceptionally has a stable +4 state that does not oxidize water. It is also considered one of the rare-earth elements. Cerium"
"SiC, AgCO, AgCN, NaHCO, NaCO, NaOCN, NaCN, NaFe(CN)NO, NaSCN, SrCO, TaC, (SCN), CSCl, TiC, WC, W(CO), CO(NH), ZnCO (NH)Ce(NO) (CAN), (NH)Ce(SO), Ce(CO), CeCl, CeF, CeF, CeO, CePO, Ce(SO), Ce(OSOCF), Ce(OSOCF) AcCl, AlCl, AmCl, NHCl, SbCl, SbCl, AsCl, BaCl, BeCl, BiCl, BCl, BrCl, CdCl, CdCl, CsCl, CaCl, Ca(OCl), CCl, CeCl, NHCl, ClO, ClO, ClF, HPtCl, ClSOH, ClSONCO, CrCl, CrCl, CrOCl, CoCl, CuCl, CuCl, CmCl, ClCN, ClO, ClO, SCl, DyCl, ErCl, EuCl, EuCl, GdCl, GaCl, GeCl, GeCl, AuCl, AuCl, HfCl, HPtCl, HoCl, HCl, HCl(aq), HOCl, InCl, InCl, ICl, IrCl, FeCl, FeCl, LaCl, PbCl, LiCl, LiClO, LuCl, MgCl, Mg(ClO), MnCl, HgCl, HgCl, Hg(ClO),"
"Johnsenite-(Ce) Johnsenite-(Ce) is a very rare mineral of the eudialyte group, with formula Na(Ce,La,Sr,Ca,[])CaMnZrWSi(SiO)(SiO)(CO)O(OH,Cl). The original formula was extended to show the presence of both the cyclic silicate groups and silicon at the M4 site, according to the nomenclature of the eudialyte group. It is the third eudialyte-group mineral with essential tungsten (after khomyakovite and manganokhomyakovite), and second with essential rare earth elements (after zirsilite-(Ce), which is the niobium-analogue of johnsenite-(Ce)). In fact, some niobium substitutes for tungsten in johnsenite-(Ce). Other characteristic feature is the presence of essential carbonate group, shared with carbokentbrooksite, golyshevite, mogovidite and zirsilite-(Ce). Johnsenite-(Ce) was discovered"
"Gagarinite-(Ce) Gagarinite-(Ce) previously zajacite-(Ce) is a rare radioactive fluoride mineral with formula Na(REECa)(REECa)F. REE refers to rare-earth elements, mostly those belonging to the lanthanide series. It crystallizes in the trigonal rhombohedral system and has a white vitreous appearance with a conchoidal fracture. It has a Mohs hardness of 3.5 and a specific gravity of 4.44 to 4.55. Zajacite is transparent with refractive indices ""n"" = 1.483 and ""n"" = 1.503. Gagarinite-(Y) is a yttrium-rich analog. It occurs as creamy to white anhedral to subhedral grains in pegmatite and aplite pods or lenses in a peralkaline igneous intrusion. It was discovered"
"Cerianite-(Ce) Cerianite-(Ce) is a relatively rare oxide mineral, belonging to uraninite group with the formula (Ce,Th)O. It is one of a few currently known minerals containing essential tetravalent cerium, the other examples being stetindite and dyrnaesite-(La). Cerianite-(Ce) is associated with alkaline rocks, mostly nepheline syenites. It may be found in carbonatites. Cerianite-(Ce) associates with minerals of the apatite group, bastnäsite-group minerals, calcite, feldspar, ""fluocerite"", ""hydromica"", ilmenite, nepheline, magnetite, ""törnebohmite"" and tremolite. It is the most simple cerium mineral known. Beside thorium cerianite-(Ce) may contain trace niobium, yttrium, lanthanum, ytterbium, zirconium and tantalum. For details on crystal structure see cerium(IV) oxide."
"Cerianite-(Ce) Cerianite-(Ce) is a relatively rare oxide mineral, belonging to uraninite group with the formula (Ce,Th)O. It is one of a few currently known minerals containing essential tetravalent cerium, the other examples being stetindite and dyrnaesite-(La). Cerianite-(Ce) is associated with alkaline rocks, mostly nepheline syenites. It may be found in carbonatites. Cerianite-(Ce) associates with minerals of the apatite group, bastnäsite-group minerals, calcite, feldspar, ""fluocerite"", ""hydromica"", ilmenite, nepheline, magnetite, ""törnebohmite"" and tremolite. It is the most simple cerium mineral known. Beside thorium cerianite-(Ce) may contain trace niobium, yttrium, lanthanum, ytterbium, zirconium and tantalum. For details on crystal structure see cerium(IV) oxide."
"towards selenide formation being lower for copernicium than for mercury. This was unexpected as the stability of the group 12 selenides tends to decrease down the group from ZnSe to HgSe, while it increases down the group for the group 14 selenides from GeSe to PbSe. Copernicium Copernicium is a synthetic chemical element with symbol Cn and atomic number 112. It is an extremely radioactive element, and can only be created in a laboratory. The most stable known isotope, copernicium-285, has a half-life of approximately 29 seconds. Copernicium was first created in 1996 by the GSI Helmholtz Centre for Heavy"
"Zirsilite-(Ce) Zirsilite-(Ce) is a very rare mineral of the eudialyte group, with formula (Na,[])(Ce,Na)CaMnZrNbSi(SiO)(SiO)O(OH)(CO)•HO. The original formula was extended to show the presence of cyclic silicate groups and the presence of silicon at the M4 site, according to the nomenclature of the eudialyte group.according to the nomenclature of eudialyte group. Zirsilite-(Ce) differs from carbokentbrooksite in cerium-dominance over sodium only. Both minerals are intimately associated. The only other currently known representative of the eudialyte group having rare earth elements (in particular cerium, as suggested by the ""-Ce)"" Levinson suffix in the name) in dominance is johnsenite-(Ce). Zirsilite-(Ce) and carbokentbrooksite occur in"
"Isotopes of cerium Naturally occurring cerium (Ce) is composed of 4 stable isotopes: Ce, Ce, Ce, and Ce, with Ce being the most abundant (88.48% natural abundance) and the only one theoretically stable; Ce, Ce, and Ce are predicted to undergo double beta decay but this process has never been observed. There are 35 radioisotopes that have been characterized, with the most stable being Ce, with a half-life of 284.893 days; Ce, with a half-life of 137.640 days and Ce, with a half-life of 32.501 days. All of the remaining radioactive isotopes have half-lives that are less than 4 days"
"and the majority of these have half-lives that are less than 10 minutes. This element also has 10 meta states. The isotopes of cerium range in atomic weight from 119 u (Ce) to 157 u (Ce). Isotopes of cerium Naturally occurring cerium (Ce) is composed of 4 stable isotopes: Ce, Ce, Ce, and Ce, with Ce being the most abundant (88.48% natural abundance) and the only one theoretically stable; Ce, Ce, and Ce are predicted to undergo double beta decay but this process has never been observed. There are 35 radioisotopes that have been characterized, with the most stable being"
"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"
"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 and potassium. The most reactive of all metals, it is pyrophoric and reacts with water even at −116 °C (−177 °F). It is the least electronegative element, with a value of 0.79 on the Pauling scale. It"
"in 1993 at Strange Lake, Quebec – Labrador, (56°20'N, 64°10'W) and was initially named for Ihor Stephan Zajac, who led the expedition responsible for its discovery, and who first recognized the presence of the new mineral. The mineral was renamed gagarinite-(Ce) in 2010 by the IMA. The new name is for Russian cosmonaut Yuri Gagarin (1934–1968). Gagarinite-(Ce) Gagarinite-(Ce) previously zajacite-(Ce) is a rare radioactive fluoride mineral with formula Na(REECa)(REECa)F. REE refers to rare-earth elements, mostly those belonging to the lanthanide series. It crystallizes in the trigonal rhombohedral system and has a white vitreous appearance with a conchoidal fracture. It has"
"Cysteine Cysteine (symbol Cys or C; ) is a semiessential proteinogenic amino acid with the formula HOCCH(NH)CHSH. The thiol side chain in cysteine often participates in enzymatic reactions, as a nucleophile. The thiol is susceptible to oxidation to give the disulfide derivative cystine, which serves an important structural role in many proteins. When used as a food additive, it has the E number E920. It is encoded by the codons UGU and UGC. Cysteine has the same structure as serine, but with one of its oxygen atoms replaced by sulfur; replacing it with selenium gives selenocysteine. (Like other natural proteinogenic"
"Loparite-(Ce) Loparite-(Ce) is a granular, brittle oxide mineral of the perovskite class. It is black to dark grey and may appear grey to white in reflected light on polished thin section with reddish brown internal reflections. It has the chemical formula of (Ce,Na,Ca)(Ti,Nb)O. Nioboloparite is a variation of Loparite-(Ce) containing niobium. Loparite occurs as a primary phase in nepheline syenite intrusios and pegmatites. It is also found replacing perovskite in carbonatites. Loparite was first described for an occurrence in the Khibiny and Lovozero massifs, Kola peninsula and northern Russia. The term originates from the word ""Lopar"", the Russian name for"
"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"
"Copernicium Copernicium is a synthetic chemical element with symbol Cn and atomic number 112. It is an extremely radioactive element, and can only be created in a laboratory. The most stable known isotope, copernicium-285, has a half-life of approximately 29 seconds. Copernicium was first created in 1996 by the GSI Helmholtz Centre for Heavy Ion Research near Darmstadt, Germany. It is named after the astronomer Nicolaus Copernicus. In the periodic table of the elements, copernicium is a d-block transactinide element and a group 12 element. During reactions with gold, it has been shown to be an extremely volatile metal, so"
"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"
"Selenocysteine Selenocysteine (symbol Sec or U, in older publications also as Se-Cys) is the 21st proteinogenic amino acid. Selenocysteine exists naturally in all three domains of life, but not in every lineage, as a building block of selenoproteins. Selenocysteine is a cysteine analogue with a selenium-containing selenol group in place of the sulfur-containing thiol group. Selenocysteine is present in several enzymes (for example glutathione peroxidases, tetraiodothyronine 5' deiodinases, thioredoxin reductases, formate dehydrogenases, glycine reductases, selenophosphate synthetase 2, methionine-R-sulfoxide reductase B1 (SEPX1), and some hydrogenases). Selenocysteine was discovered by biochemist Thressa Stadtman at the National Institutes of Health. Selenocysteine has a"
"Ceric ammonium nitrate Ceric ammonium nitrate (CAN) is the inorganic compound with the formula (NH)Ce(NO). This orange-red, water-soluble cerium salt is a specialised oxidizing agent in organic synthesis and a standard oxidant in quantitative analysis. The anion is generated by dissolving in hot concentrated HNO. The salt consists of the anion and a pair of NH counter ions. The ammonium ions are not involved in the oxidising reactions of this salt. In the anion each nitrate group is chelated to the cerium atom in a bidentate manner as shown below: The anion has T (idealized O) molecular symmetry. The CeO"
"Ce.45 La.20 Nd.20 Pr.09 Sm.08 Gd.06)(Mg1.81 Fe.25)Al.97 Si3.0(OH)1.25 F.88 O10.99 from which the standard formula is then derived after applying Levinson’s rules for renaming REE minerals. Before any of these highly technological analyses were performed on dollaseite-(Ce) specimens, mistakes were made on the composition of the mineral. After further analysis were made it was determined that dollaseite-(Ce) was not the Magnesium (Mg) analogue of allanite as originally believed by Gaijer (1927) and was renamed. Geijer (1927) however, was not the only one to have had reported minerals with compositions that would be similar to an Mg analogue of allanite. Enami"
"and Ce are theoretically expected to undergo inverse double beta decay to isotopes of barium, and the heaviest isotope Ce is expected to undergo double beta decay to Nd or alpha decay to Ba. Additionally, Ce would release energy upon spontaneous fission. None of these decay modes have yet been observed, though the double beta decay of Ce, Ce, and Ce has been experimentally searched for. The current experimental limits for their half-lives are: All other cerium isotopes are synthetic and radioactive. The most stable of them are Ce with a half-life of 284.9 days, Ce with a half-life of"
"Xenon Xenon is a chemical element with symbol Xe and atomic number 54. It is a colorless, dense, odorless noble gas found in the Earth's atmosphere in trace amounts. Although generally unreactive, xenon can undergo a few chemical reactions such as the formation of xenon hexafluoroplatinate, the first noble gas compound to be synthesized. Xenon is used in flash lamps and arc lamps, and as a general anesthetic. The first excimer laser design used a xenon dimer molecule (Xe) as the lasing medium, and the earliest laser designs used xenon flash lamps as pumps. Xenon is used to search for"
"Silicon Silicon is a chemical element with symbol Si and atomic number 14. It is a hard and brittle crystalline solid with a blue-grey metallic lustre; and it is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic table: carbon is above it; and germanium, tin, and lead are below it. It is relatively unreactive. Because of its large chemical affinity for oxygen, it was not until 1823 that Jöns Jakob Berzelius was first able to prepare it and characterize it in pure form. Its melting and boiling points of 1414 °C and 3265"
"Ce under alkaline conditions. The cerium anomaly relates to the decrease in solubility, which accompanies the oxidation of Ce(III) to Ce(IV). Under reducing conditions, Ce is relatively soluble, while under oxidizing conditions CeO precipitates. Sediments deposited under oxic or anoxic conditions can preserve on the long term the geochemical signature of Ce or Ce upon reserve that no early diagenetic transformation altered it. Cerium can occur in nature as a 3+ or 4+ ion and is a compatible element (at 4+ valency) in zircon and less commonly in silica. Thomas ""et al."", (2003) state that “terrestrial zircons commonly show a"
"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"
"oxide and siliceous beryllium (ASTM D7458). Beryllium Beryllium is a chemical element with symbol Be and atomic number 4. It is a relatively rare element in the universe, usually occurring as a product of the spallation of larger atomic nuclei that have collided with cosmic rays. Within the cores of stars beryllium is depleted as it is fused and creates larger elements. It is a divalent element which occurs naturally only in combination with other elements in minerals. Notable gemstones which contain beryllium include beryl (aquamarine, emerald) and chrysoberyl. As a free element it is a steel-gray, strong, lightweight and"
"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"
"Parisite-(Ce) Parisite is a rare mineral consisting of cerium, lanthanum and calcium fluoro-carbonate, Ca(Ce,La)(CO)F. Parisite is mostly parisite-(Ce), but when neodymium is present in the structure the mineral becomes parisite-(Nd). It is found only as crystals, which belong to the trigonal or monoclinic pseudo-hexagonal system and usually have the form of acute double pyramids terminated by the basal planes; the faces of the hexagonal pyramids are striated horizontally, and parallel to the basal plane there is a perfect cleavage. The crystals are hair-brown in color and are translucent. The hardness is 4.5 and the specific gravity is 4.36. Light which"
"Cerium anomaly The cerium anomaly, in geochemistry, is the phenomenon whereby cerium (Ce) concentration is either depleted or enriched in a rock relative to the other rare-earth elements (REEs). A Ce anomaly is said to be ""negative"" if Ce is depleted relative to the other REEs and is said to be ""positive"" if Ce is enriched relative to the other REEs. Cerium is a rare-earth element (lanthanide) characterized by two different redox states: III and IV. Contrary to other lanthanide elements, which are only trivalent (with the notable exception of Eu), Ce can be oxidized by atmospheric oxygen (O) to"
"Germanium Germanium is a chemical element with symbol Ge and atomic number 32. It is a lustrous, hard, grayish-white metalloid in the carbon group, chemically similar to its group neighbors tin and silicon. Pure germanium is a semiconductor with an appearance similar to elemental silicon. Like silicon, germanium naturally reacts and forms complexes with oxygen in nature. Because it seldom appears in high concentration, germanium was discovered comparatively late in the history of chemistry. Germanium ranks near fiftieth in relative abundance of the elements in the Earth's crust. In 1869, Dmitri Mendeleev predicted its existence and some of its properties"
"an Mg analogue of allanite, now known as dissakisite-(Ce). Dollaseite-(Ce), although not very well known is part of a broad group of minerals, the epidote group which are primarily silicates, the most abundant type of minerals on earth. Dollaseite-(Ce) forms as dark-brown subhedral crystals primarily in Sweden mines. With the ideal chemical formula, CaREEMgAlSiO,(OH)F, dollaseite-(Ce) can be partially identified by its rare content of the REE (rare earth element) Ce. With a general formula for the epidote group of AMSiOH dollaseite-(Ce) receives its formula of CaREEMgAlSiO,(OH)F based on data from electron-microprobe analytical procedures. The results give the empirical formula (Ca.91"