All articles starting with M
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Metalla
Metalla, Roman mining settlement and road station in SW Sardinia's Iglesiente, on the via a Tibulas Sulcis between Neapolis and Sulci, 30 Roman miles from each; identified near Antas, Fluminimaggiore, with the temple of Sardus Pater.
Metallaphotoredox catalysis
Metallaphotoredox catalysis is a dual-catalyst synthetic method combining a metal cross-coupling catalyst, usually nickel, with a visible-light photocatalyst, first reported in 2014 to couple sp3 fragments.
Metallaphotoredox decarboxylative coupling
Metallaphotoredox decarboxylative coupling is a dual-catalytic organic reaction, first reported in 2014 by the Doyle and MacMillan groups, combining a photocatalyst and nickel to couple carboxylic acids with aryl halides.
Metallaphotoredox decarboxylative cross-coupling
Metallaphotoredox decarboxylative cross-coupling is a dual-catalytic organic reaction in which a photoredox catalyst turns carboxylic acids into alkyl radicals that a nickel catalyst couples with organic halides.
Metalli Ulpiani
Metalli Ulpiani, "the Ulpian mines", were Roman imperial ore districts named for Trajan (Ulpius), known from nummi metallorum coin legends (Delmatici, Pannonici, Dardanici), fiscus-run under procuratores, renamed metalla Aureliana under Marcus Aurelius.
Metallic bonding
Metallic bonding, first modeled by Paul Drude's early-1900s electron sea theory, is the electrostatic attraction between positive metal centers and delocalized valence electrons, explaining metals' conductivity and luster.
Metallic hydrogen
Metallic hydrogen, also called hydrogen metal, is a high-pressure phase of hydrogen that conducts electricity like a metal and is believed to fill Jupiter and Saturn.
Metallic microlattice
A metallic microlattice is an ultralight cellular material made of a periodic three-dimensional network of hollow metal struts, first reported by HRL Laboratories in Malibu, California, in 2011.
Metallic oxygen
Metallic oxygen is oxygen that conducts electricity like a metal, reached under extreme pressure of about 96 GPa in the solid or 1.2 Mbar as a hot dense fluid.
Metallic uranium fuel
Metallic uranium fuel is nuclear fuel made of uranium metal or alloys such as U-Zr and U-Mo rather than ceramic uranium dioxide, used mainly in fast and research reactors.
Metallic water
Metallic water is water that has acquired the electrical properties of a metal, first prepared under terrestrial conditions in 2021 as a transient gold-colored layer doped with electrons.
Metallica
Metallica is an American heavy metal band that became a defining force in thrash metal. The group was inducted into the Rock & Roll Hall of Fame in 2009.
Metallica (album)
Metallica (The Black Album), Metallica's self-titled fifth studio album, released August 12, 1991, produced by Bob Rock; debuted at #1 on the Billboard 200, 2x Diamond RIAA, about 30 million copies sold.
Metallica discography
Metallica discography: the American heavy metal band's catalog, from Kill 'Em All (1983, Megaforce) through 72 Seasons (2023), plus S&M2, Lulu, and Load/ReLoad remasters (2025–2026). Black Album sold 15–16 million worldwide, 16× platinum.
Metallica: Some Kind of Monster
Metallica: Some Kind of Monster is a 2004 documentary by Joe Berlinger and Bruce Sinofsky covering Metallica's St. Anger sessions, Jason Newsted's exit, Hetfield's rehab, therapist Phil Towle, and Trujillo's audition.
Metallicity
Metallicity, also called stellar metallicity, is the fraction of a star's or galaxy's baryonic mass made of elements heavier than helium, including non-metallic ones like carbon and oxygen.
Metallization (semiconductor fabrication)
Metallization is the semiconductor-fabrication step that deposits metal layers onto a wafer, forming the contacts, vias, and interconnects that link transistors into a working circuit.
Metallo
Metallo (John Corben) is a DC Comics supervillain and cyborg enemy of Superman powered by a Kryptonite heart. Debuting in Action Comics #252 (May 1959) by Robert Bernstein and Al Plastino, distinct from the 1942 one-L "Metalo", with post-Crisis, New 52 Metal-Zero, and Dawn of DC "Rise of Metallo" versions.
Metallocene catalyst
A metallocene catalyst is an organometallic catalyst for olefin polymerization, typically a Group 4 metallocene activated by methylaluminoxane, producing polyethylene and polypropylene with narrow molecular weight distributions.
Metalloenzyme
Metalloenzyme: an enzyme containing one or more metal ions essential for function (IUPAC). About 40% of all enzymes; metals catalyze, transfer electrons, or stabilize structure; includes artificial metalloenzymes and drug targets.
Metallography
Metallography is a materials characterization technique that reveals the microstructure of metals and alloys by sectioning, polishing, etching, and imaging with optical or electron microscopy.
Metalloid
A metalloid is a chemical element whose properties lie between those of metals and nonmetals; the most commonly cited members are boron, silicon, germanium, arsenic, antimony, and tellurium.
Metalloprotease inhibitor
Metalloprotease inhibitors block zinc-dependent proteases, chiefly matrix metalloproteinases, usually via zinc-chelating groups like hydroxamates; only doxycycline (Periostat) is approved, for periodontitis, after widespread trial failures.
Metalloprotein
Metalloprotein: a protein containing one or more tightly bound metal ions (iron, zinc, copper, calcium, others) as structural, catalytic, or regulatory cofactors; roughly a third to 40% of proteomes, studied via metalloproteomics and engineered as artificial metalloenzymes.
Metalloradical catalysis
Metalloradical catalysis is a catalytic method in organic chemistry in which open-shell transition-metal complexes, chiefly cobalt(II) porphyrins, generate and control radical intermediates to form chemical bonds selectively under neutral conditions.
Metallosupramolecular self-healing polymers
Metallosupramolecular self-healing polymers are polymer networks whose chains are joined by reversible metal-ligand coordination bonds rather than permanent covalent cross-links, so after a cut or scratch the network re-forms and recovers its mechanical function.
Metallothionein
Metallothionein (MT): low-molecular-weight (6–7 kDa), cysteine-rich metal-binding protein discovered in horse kidney in 1957; binds up to 7 metal ions in α/β domains; human isoforms MT1–MT4; protects against cadmium toxicity.
Metallurgical Corp of China
Metallurgical Corp of China (MCC) is a Chinese state-owned engineering, construction, and mining company that built WISCO, Baogang, and Baosteel, and has been a subsidiary of China Minmetals since 2015.
Metallurgical Laboratory
The Metallurgical Laboratory, or Met Lab, was a secret Manhattan Project laboratory at the University of Chicago, where the first nuclear chain reaction was achieved in 1942.
Metallurgy
Metallurgy is the art and science of extracting metals from their ores and modifying them for use, spanning extraction steps like smelting and refining, and physical processes like alloying and heat treatment.