geologia: Ytterbium

Evidence: 66 • authority: 72

Lutetium is a chemical element; it has symbol Lu and atomic number 71. It is a silvery white metal which resists corrosion in dry air, but not in moist air. Lutetium is the last element in the lanthanide series, and it is traditionally counted among the rare earth elements; it can also be classified as the first element of the sixth-period transition metals. Lutetium was independently discovered in 1907 by French scientist Georges Urbain, Austrian mineralogist Baron Carl Auer von Welsbach, and American chemist Charles James. All of these researchers found lutetium as an impurity in ytterbium. The dispute on the priority of the discovery occurred shortly after, with Urbain and Welsbach accus…

Evidence: 66 • authority: 72

Ytterbium is a chemical element; it has symbol Yb and atomic number 70. It is a metal, the fourteenth element in the lanthanide series, which is the basis of the relative stability of its +2 oxidation state. Like the other lanthanides, its most common oxidation state is +3, as in its oxide, halides, and other compounds. In aqueous solution, like compounds of other late lanthanides, soluble ytterbium compounds form complexes with nine water molecules. Because of its closed-shell electron configuration, its density, melting point and boiling point are much lower than those of most other lanthanides. In 1878, Swiss chemist Jean Charles Galissard de Marignac separated from the rare earth "erbia…

Evidence: 58 • authority: 72

The rare-earth elements (REE), also called rare-earth metals, or rare earths, are a set of 17 nearly indistinguishable lustrous silvery-white soft heavy metals. The 15 lanthanides (or lanthanoids), along with scandium, and yttrium, are usually included as rare earths. Compounds containing rare-earth elements have diverse applications in electrical and electronic components, lasers, glass, magnetic materials, and industrial processes. Rare-earths are to be distinguished from critical minerals, which are materials of strategic or economic importance that are defined differently by different countries, and rare-earth minerals, which are minerals that contain one or more rare-earth elements as…

Evidence: 50 • authority: 92

Rare-Earth Elements at the Interface of Chemistry and Cancer Therapy.. Rare-earth elements (REEs), which include the entire lanthanide series together with scandium and yttrium, have unique electronic configurations and coordination chemical properties that provide them with special magnetic, optical, and redox abilities. Generally used for diagnostic imaging and theranostic applications, increasing evidence emphasizes their potential as direct anticancer agents. This review aims to present a thorough investigation of the studies published in the last ten years that focus on the intrinsic anticancer properties of REE-based molecular complexes and nanostructures, without discussing their rec…

Evidence: 50 • authority: 72

Yttrium is a chemical element; it has symbol Y and atomic number 39. It is a silvery-metallic transition metal chemically similar to the lanthanides and has often been classified as a rare-earth element. Yttrium is almost always found in combination with lanthanide elements in rare-earth minerals and is never found in nature as a free element. 89Y is the only stable isotope and the only isotope found in the Earth's crust. The most important present-day use of yttrium is as a component of phosphors, especially those used in LEDs. It was once widely used in the red phosphors in the cathode ray tubes of television sets. Yttrium is also used in the production of electrodes, electrolytes, electr…

Evidence: 50 • authority: 72

The abundance of the chemical elements is a measure of the occurrences of the chemical elements relative to all other elements in a given environment. Abundance is measured in one of three ways: by mass fraction (in commercial contexts often called weight fraction), by mole fraction (fraction of atoms by numerical count, or sometimes fraction of molecules in gases), or by volume fraction. Volume fraction is a common abundance measure in mixed gases such as planetary atmospheres, and is similar in value to molecular mole fraction for gas mixtures at relatively low densities and pressures, and ideal gas mixtures. Most abundance values in this article are given as mass fractions. The abundance…

Evidence: 42 • authority: 72

Samarium is a chemical element; it has symbol Sm and atomic number 62. It is a moderately hard silvery metal that slowly oxidizes in air. Being a typical member of the lanthanide series, samarium usually has the oxidation state +3. Compounds of samarium(II) are also known, most notably the monoxide SmO, monochalcogenides SmS, SmSe and SmTe, as well as samarium(II) iodide. Discovered in 1879 by French chemist Paul-Émile Lecoq de Boisbaudran, samarium was named after the mineral samarskite from which it was isolated. The mineral was named after a Russian mine official, Vassili Samarsky-Bykhovets, who thus became the first person to have a chemical element named after him, though the name was…

Evidence: 42 • authority: 72

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 its heavier homologues strontium and barium. It is the fifth most abundant element in Earth's crust, and the third most abundant metal, after iron and aluminium. The most common calcium compound on Earth is calcium carbonate, found in limestone and the fossils of early sea life; gypsum, anhydrite, fluorite, and apatite are also sources of calcium. The name comes from the Latin word calx (meaning "lime"), which was obtained from heating limestone. Some c…

Evidence: 42 • authority: 72

Thulium is a chemical element; it has symbol Tm and atomic number 69. It is the thirteenth element in the lanthanide series of metals. It is the second-least abundant lanthanide in the Earth's crust, after radioactively unstable promethium. It is an easily workable metal with a bright silvery-gray luster. It is fairly soft and slowly tarnishes in air. Despite its high price and rarity, thulium is used as a dopant in solid-state lasers. It has no significant biological role and is not particularly toxic. Artificial radioactive isotopes of thulium are used as radiation sources in some portable X-ray devices. In 1879, the Swedish chemist Per Teodor Cleve separated two previously unknown compon…

Evidence: 42 • authority: 92

Life-Cycle Assessment of Nd-Fe-B Rare Earth Magnet Production.. Rare-earth elements are strategic materials essential for renewable energy, electronics, and electric mobility. The growing demand emphasizes the need for a sustainable and efficient supply, considering environmental and economic aspects. Among their main applications are neodymium-iron-boron (Nd-Fe-B) permanent magnets, whose production chain presents significant environmental impactsfrom mining to final manufacturing. This study assesses the life cycle of Nd-Fe-B magnets in the Brazilian context, following ISO 14040 and ISO 14044 standards. System modeling was performed in Sankey software, and environmental impacts were calc…

Evidence: 42 • authority: 92

Comparing the Behavioral Impacts of Heavy Metals and Rare Earth Elements on Black Soldier Fly (<i>Hermetia illucens</i>) Larvae.. Heavy metals (HMs) and rare earth elements (REEs) increasingly co-occur in environmental waste streams and soils, yet their comparative neurotoxic mechanisms and sublethal effects on invertebrate decomposers remain poorly understood. This study used black soldier fly larvae (BSFL, Hermetia illucens ) to perform a comparative behavioral and transcriptomic assessment of 23 HMs and 16 REEs across two acute exposure concentrations. High-throughput video tracking and phenomic analysis showed HMs produced broader disruption than REEs, with low-concentration…