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  • Halleck, Henry Wager (United States general)

    Henry W. Halleck, Union officer during the American Civil War who, despite his administrative skill as general in chief (1862–64), failed to achieve an overall battle strategy for Union forces. A graduate of the U.S. Military Academy at West Point, N.Y. (1839), Halleck was commissioned in the

  • hälleflinta (rock)

    Hälleflinta, (Swedish: “rock flint”), white, gray, yellow, greenish, or pink fine-grained rock that consists of quartz intimately mixed with feldspar. It is very finely crystalline, resembling the matrix of many silica-rich (acid) igneous rocks. Many examples are banded or striated; others contain

  • Hallein (Austria)

    Hallein, town, north-central Austria, on the Salzach River just south of Salzburg city. Founded in the 12th century and chartered in 1230, Hallein profited from the nearby Dürrnberg saltworks, in operation since the 13th century. Old landmarks include the Classical parish church (15th century),

  • Hallel (Judaism)

    Hallel, (Hebrew: “Praise”), Jewish liturgical designation for Psalms 113–118 (“Egyptian Hallel”) as read in synagogues on festive occasions. In ancient times Jews recited these hymns on the three Pilgrim Festivals, when they offered their required sacrifices in the Temple of Jerusalem. The Psalms

  • Hallelujah (film by Vidor)

    history of the motion picture: Postsynchronization: …swamplands in the all-black musical Hallelujah (1929). Vidor shot the action on location without sound, using a freely moving camera. Later, in the studio, he added to the film a separately recorded sound track containing both naturalistic and impressionistic effects. In the following year Lewis Milestone’s All Quiet on the…

  • Hallelujah (song by Cohen)

    Leonard Cohen: …became Cohen’s best-known song, “Hallelujah.” Although it did not initially receive much attention, the single gained widespread popularity when covered by Jeff Buckley in 1994. The ballad was later performed or recorded by hundreds of artists and featured in soundtracks of TV shows and films.

  • hallelujah (religious music)

    Hallelujah, Hebrew liturgical expression meaning “praise ye Yah” (“praise the Lord”). It appears in the Hebrew Bible in several psalms, usually at the beginning or end of the psalm or in both places. In ancient Judaism it was probably chanted as an antiphon by the Levite choir. In the New Testament

  • Hallelujah Chicken Run Band (Zimbabwean music group)

    chimurenga: …early 1970s, Mapfumo formed the Hallelujah Chicken Run Band. Among his first and most significant initiatives with the group was to change the language of the songs from English, which was associated with the white-minority administration, to Shona, which was spoken by the majority of the country’s black population. While…

  • Hallelujah Chorus (work by Handel)

    Messiah: …source of the familiar “Hallelujah Chorus.” Messiah is by far the most frequently performed of all oratorios.

  • Hallelujah Psalm

    biblical literature: Psalms: …pilgrim songs in origin, the Hallelujah Psalms, and a group of 55 psalms with a title normally taken to mean “the choirmaster.”

  • Hallelujah Trail, The (film by Sturges [1965])

    John Sturges: Later films: The Hallelujah Trail (1965) was a western spoof centring on a cavalry colonel (Lancaster) who tries to deliver 40 wagonloads of whiskey to miners in the face of stiff opposition from temperance activists (led by Lee Remick). The overlong and uneven film was widely panned.…

  • Hallelujah, I’m a Bum! (film by Milestone [1933])

    Lewis Milestone: Films of the 1930s: Hallelujah, I’m a Bum! (1933), an inventive musical drama that featured rhyming dialogue, failed to find an audience, despite starring Al Jolson. The Captain Hates the Sea (1934) was a zany comedy that tried to blend such disparate elements as John Gilbert, Victor McLaglen, and…

  • Hallenkirche (architecture)

    Hall church, church in which the aisles are approximately equal in height to the nave. The interior is typically lit by large aisle windows, instead of a clerestory, and has an open and spacious feeling, as of a columned hall. Hall churches are characteristic of the German Gothic period. There are

  • Haller’s organ (arachnid anatomy)

    tick: …of a sensory pit (Haller’s organ) on the end segment of the first of four pairs of legs. Eyes may be present or absent.

  • Haller, Albrecht von (Swiss biologist)

    Albrecht von Haller, Swiss biologist, the father of experimental physiology, who made prolific contributions to physiology, anatomy, botany, embryology, poetry, and scientific bibliography. At the University of Göttingen (1736–53), where he served as professor of medicine, anatomy, surgery, and

  • Haller, Bertold (Swiss religious reformer)

    Bertold Haller, Swiss religious Reformer who was primarily responsible for bringing the Reformation to Bern. Having arrived at Bern as a schoolmaster in 1513, Haller became canon at the cathedral in 1520. About the same time, he fell under the influence of the Protestant Reformer Huldrych Zwingli.

  • Haller, Ernest (American cinematographer)
  • Hallerman–Streiff–François syndrome (pathology)

    progeria: A third condition, Hallerman-Streiff-François syndrome, is characterized by the presence of progeria in combination with dwarfism and other features of abnormal growth. Progeria is extremely rare; for example, the global incidence of Hutchinson-Gilford progeria syndrome is approximately one in every four to eight million births.

  • Halles, The (market, Paris, France)

    Paris: The Halles: Several streets northwest of the Hôtel de Ville is the quarter of the Halles, which was from 1183 to 1969 the central market (ultimately a wholesale market for fresh products) of Paris. When the market moved out to a new location at Rungis,…

  • Hallett, Cape (cape, Antarctica)

    Ross Sea: …Volcanics) consisting of Cape Adare, Cape Hallett, Mount Melbourne, Franklin and Ross islands, on the western coast, and a number of lesser-known centres in western Marie Byrd Land, on the eastern coast.

  • Hallett, Stephen (American architect)

    United States Capitol: …the runner-up in the competition, Stephen Hallet. Hallet attempted to alter many of Thornton’s plans and was quickly replaced, first by George Hadfield and later by James Hoban, the architect who designed the White House.

  • Halley’s Comet (astronomy)

    Halley’s Comet, the first comet whose return was predicted and, almost three centuries later, the first to be imaged up close by interplanetary spacecraft. In 1705 English astronomer Edmond Halley published the first catalog of the orbits of 24 comets. His calculations showed that comets observed

  • Halley, Edmond (British scientist)

    Edmond Halley, English astronomer and mathematician who was the first to calculate the orbit of a comet later named after him. He is also noted for his role in the publication of Isaac Newton’s Philosophiae Naturalis Principia Mathematica. Halley began his education at St. Paul’s School, London. He

  • Halley, Edmund (British scientist)

    Edmond Halley, English astronomer and mathematician who was the first to calculate the orbit of a comet later named after him. He is also noted for his role in the publication of Isaac Newton’s Philosophiae Naturalis Principia Mathematica. Halley began his education at St. Paul’s School, London. He

  • Hallgrímskirkja (church, Saurbaer, Iceland)

    Hallgrímur Pétursson: The Hallgrímskirkja, a memorial church built in the poet’s honour at Reykjavík, is one of the largest and finest churches in Iceland.

  • Hallgrímsson, Jónas (Icelandic poet)

    Jónas Hallgrímsson, one of the most popular of Iceland’s Romantic poets. Descended from a family of poets, Hallgrímsson lost his father, a chaplain, at age nine. Entering the University of Copenhagen in 1829, Hallgrímsson studied law, science, and literature. In 1835, with other Icelandic students

  • Halliburton (American company)

    Halliburton, American oil-field services, engineering, and construction company that operates worldwide. It is a global leader in the so-called “upstream” oil industry (petroleum exploration and production). Company headquarters offices are in Houston, Texas, and Dubai, United Arab Emirates.

  • Halliburton Oil Well Cementing Co. (American company)

    Halliburton, American oil-field services, engineering, and construction company that operates worldwide. It is a global leader in the so-called “upstream” oil industry (petroleum exploration and production). Company headquarters offices are in Houston, Texas, and Dubai, United Arab Emirates.

  • Halliburton, Erle P. (American businessman)

    Halliburton: Origin and growth: Company founder Erle P. Halliburton learned how cement can be used to protect and seal oil-well bores while employed by the Perkins Oil Well Cementing Co. in California in 1916. He was soon dismissed from that company, supposedly for changing procedures without authorization, and eventually found his…

  • Halliburton, Richard (American writer)

    Richard Halliburton, American travel and adventure writer who spent most of his adult life exploring the world. After his sophomore year at Princeton University, Halliburton found his way to New Orleans, joined a crew on a freighter ship, and sailed across the Atlantic Ocean. After roaming about

  • Halliday, M. A. K. (British linguist)

    Michael Halliday, British linguist, teacher, and proponent of neo-Firthian theory who viewed language basically as a social phenomenon. Halliday obtained a B.A. in Chinese language and literature from the University of London and then did postgraduate work in linguistics, first at Peking University

  • Halliday, Michael (British linguist)

    Michael Halliday, British linguist, teacher, and proponent of neo-Firthian theory who viewed language basically as a social phenomenon. Halliday obtained a B.A. in Chinese language and literature from the University of London and then did postgraduate work in linguistics, first at Peking University

  • Halliday, Michael Alexander Kirkwood (British linguist)

    Michael Halliday, British linguist, teacher, and proponent of neo-Firthian theory who viewed language basically as a social phenomenon. Halliday obtained a B.A. in Chinese language and literature from the University of London and then did postgraduate work in linguistics, first at Peking University

  • Hallidie Building (building, San Francisco, California, United States)

    construction: Use of steel and other metals: …facade, was that of the Hallidie Building (1918) in San Francisco. The first multistory structure with a full glass curtain wall was the A.O. Smith Research Building (1928) in Milwaukee by Holabird and Root; in it the glass was held by aluminum frames, an early use of this metal in…

  • Hallidie, Andrew (American inventor)

    streetcar: …cable car, the invention of Andrew Hallidie, was introduced in San Francisco on Sacramento and Clay streets in 1873. The cars were drawn by an endless cable running in a slot between the rails and passing over a steam-driven shaft in the powerhouse. The system was well-adapted for operation on…

  • halling (Norwegian dance)

    Halling, vigorous Norwegian folk dance for couples. The name derives from Hallingdal, a valley in southern Norway. Two or three males may dance in rivalry, performing difficult leaps, kicks, and other acrobatic stunts to demonstrate vigour and virility. The halling is one of a number of European

  • Halliwell, Geraldine Estelle (British entertainer)

    Spice Girls: …were Ginger Spice (byname of Geraldine Estelle Halliwell; b. August 6, 1972, Watford, England), Sporty Spice (byname of Melanie Jayne Chisholm; b. January 12, 1974, Liverpool, England), Posh Spice (byname of Victoria Adams [later Victoria Beckham]; b. April 7, 1975, Hertfordshire, England), Scary Spice (byname of Melanie Janine Brown; b.…

  • Halliwell, K. L. (British author)

    Joe Orton: …encouragement of his lifelong companion, K.L. Halliwell. A handful of novels the pair wrote at this time were not published, however, and it was not until 1964 that Orton had his first success, when his radio play The Ruffian on the Stair was broadcast by the BBC. From then until…

  • hallmark (metalwork)

    Hallmark, symbol or series of symbols stamped on an article of gold or silver to denote that it conforms to legal standards that define the maximum proportion of base metals that may be alloyed with pure gold or silver for hardening or other purposes; in broader terms, any mark distinguishing

  • Hallmark Cards, Inc. (American company)

    Joyce C. Hall: …and chief executive (1910–66) of Hallmark Cards, Inc., the largest greeting-card manufacturer in the world.

  • Hallock, Mary Anna (American writer and artist)

    Mary Anna Hallock Foote, American novelist and illustrator whose vivid literary and artistic productions drew on life in the mining communities of the American West. Mary Hallock grew up in a literary home and early displayed artistic talent. She attended Poughkeepsie (New York) Female Collegiate

  • Hallopora (fossil bryozoan genus)

    Hallopora, genus of extinct bryozoans (moss animals) found as fossils in Ordovician to Silurian marine rocks (from 505 to 408 million years old). Hallopora is distinguished by the large size of its pores and by its internal structure. Various species of Hallopora are known, some of them useful for

  • Halloween (film by Carpenter [1978])

    serial murder: History: …examples of the latter were Halloween (1978) and Friday the 13th (1980). Jack the Ripper was a character in Pandora’s Box (1904) and other plays by the German writer Frank Wedekind. Wedekind’s work was in turn the basis of the opera Lulu (1937), by Alban Berg.

  • Halloween

    Halloween, a holiday observed on October 31, the evening before All Saints’ (or All Hallows’) Day. The celebration marks the day before the Western Christian feast of All Saints and initiates the season of Allhallowtide, which lasts three days and concludes with All Souls’ Day. In much of Europe

  • Hallowell, A. Irving (American anthropologist)

    A. Irving Hallowell, U.S. cultural anthropologist known for his work on the North American Indians, especially the Ojibwa. Hallowell received his early training at the Wharton School of Finance and Commerce of the University of Pennsylvania and was a social worker in Philadelphia while doing

  • Hallowell, Alfred Irving (American anthropologist)

    A. Irving Hallowell, U.S. cultural anthropologist known for his work on the North American Indians, especially the Ojibwa. Hallowell received his early training at the Wharton School of Finance and Commerce of the University of Pennsylvania and was a social worker in Philadelphia while doing

  • Hallowmas (Christianity)

    All Saints’ Day, in the Christian church, a day commemorating all the saints of the church, both known and unknown, who have attained heaven. It is celebrated on November 1 in the Western churches and on the first Sunday after Pentecost in the Eastern churches. In Roman Catholicism, the feast is

  • Halloy, Jean-Baptiste-Julien d’Omalius d’ (Belgian geologist)

    Jean-Baptiste-Julien d’ Omalius d’Halloy, Belgian geologist who was an early proponent of evolution. D’Omalius was educated first in Liège and afterward in Paris. While a youth he became interested in geology (over the protests of his parents) and, having an independent income, was able to devote

  • halloysite (mineral)

    Halloysite, clay mineral that occurs in two forms: one is similar in composition to kaolinite, and the other is hydrated. Both forms have a lower specific gravity than kaolinite, are fibrous rather than platy, and may exhibit a prismatic tubular shape.

  • Halls of Montezuma (film by Milestone [1950])

    Lewis Milestone: War dramas: …returned to war dramas with Halls of Montezuma (1950), a rousing if conventional tale about marines who are tasked with finding a Japanese rocket base; the exceptional cast included Richard Widmark, Jack Palance, Karl Malden, and Jack Webb.

  • Hallstatt (archaeological site, Austria)

    Hallstatt, site in the Upper Austrian Salzkammergut region where objects characteristic of the late Bronze Age and early Iron Age (from c. 1100 bc) were first identified; the term Hallstatt now refers generally to late Bronze and early Iron Age culture in central and western Europe. During

  • Hallstatt culture (European culture)

    Hallstatt: …were first identified; the term Hallstatt now refers generally to late Bronze and early Iron Age culture in central and western Europe. During excavation between 1846 and 1899, more than 2,000 graves were found at Hallstatt. The majority fall into two groups, an earlier (c. 1100/1000 to c. 800/700 bc)…

  • Hallstein Doctrine (European history)

    Germany: Ostpolitik and reconciliation, 1969–89: …by the terms of the Hallstein Doctrine (named for one of Adenauer’s key foreign-policy aides, Walter Hallstein), the Bonn authorities had refused to maintain diplomatic relations with all those countries (other than the Soviet Union) that recognized the German Democratic Republic. Now the Brandt-Scheel cabinet reversed these policies by opening…

  • Hallucigenia (fossil animal)

    Burgess Shale: Such unusual fossils as Hallucigenia, a creature with a long tubular body and two rows of tall dorsal spines; Wiwaxia, an oval creature with two rows of spines down its plated back; and Opabinia, which had five eyes and a long nozzle, have led many scientists to conclude that…

  • Hallucinated City (work by Andrade)

    Mário de Andrade: …from his Paulicéia Desvairada (1922; Hallucinated City), was greeted by catcalls, but it has since been recognized as the single most significant influence on modern Brazilian poetry.

  • hallucination (psychology)

    Hallucination, the experience of perceiving objects or events that do not have an external source, such as hearing one’s name called by a voice that no one else seems to hear. A hallucination is distinguished from an illusion, which is a misinterpretation of an actual stimulus. A historical survey

  • Hallucinations (book by Sacks)

    Oliver Sacks: Hallucinations (2012) inventoried conditions and circumstances—from epilepsy to drug use to sensory deprivation—that can cause hallucinations and chronicled the effects of illusory neurological phenomena on those who experienced them. Among his autobiographical works were Uncle Tungsten: Memories of a Chemical Boyhood (2001), Oaxaca Journal (2002),…

  • hallucinogen (pharmacology)

    Hallucinogen, substance that produces psychological effects that tend to be associated with phenomena such as dreams or religious exaltation or with mental disorders such as schizophrenia. Hallucinogens produce changes in perception, thought, and feeling, ranging from distortions of what is sensed

  • hallux (anatomy)

    human muscle system: Changes in the muscles of the lower limb: …the flexor muscles of the big toe are developed to provide the final push off in the walking cycle. Muscles of all three compartments of the modern human lower leg contribute to making the foot a stable platform, which nonetheless can adapt to walking over rough and sloping ground.

  • Hallward, Gloria Grahame (American actress)

    The Big Heat: …enjoys considerable screen chemistry with Gloria Grahame as the ill-treated mob moll. Lee Marvin makes an early screen appearance as a sadistic gangster.

  • Hallyday, Johnny (French singer and actor)

    Céline Dion: …one with French rock legend Johnny Hallyday, and Loved Me Back to Life (2013), which featured a duet with Stevie Wonder, among others.

  • hallyu (Korean culture)

    Bae Yong-Jun: The trend became known as hallyu, or “Korean Wave,” and it seemed to peak with the KBS drama series Gyeoul yeonga (2002; Winter Sonata). Though the story was a typical tale of star-crossed lovers, the performances of Bae and costar Choi Ji-Woo captivated the country. The Japanese network Nippon Hoso…

  • Halm Paşa, Said (Turkish statesman)

    World War I: The Turkish entry: …therefore persuaded the grand vizier, Said Halim Paşa, to make a secret treaty (negotiated late in July, signed on August 2) pledging Turkey to the German side if Germany should have to take Austria-Hungary’s side against Russia. The unforeseen entry of Great Britain into the war against Germany alarmed the…

  • Halma (game)

    Halma, (Greek: “jump”), checkers-type board game, invented about 1880, in which players attempt to move a number of pieces from one corner of a square board containing 256 squares to the opposite corner. The first to transfer all of his pieces is the winner. In the two-handed game, each player has

  • Halmahera (island, Indonesia)

    Halmahera, largest island of the Moluccas, in Indonesia; administratively, it is part of the propinsi (or provinsi; province) of North Maluku (Maluku Utara). The island, located between the Molucca Sea (west) and the Pacific Ocean (east), consists of four peninsulas enclosing three great bays

  • Halmay, Zoltán (Hungarian swimmer)

    Zoltán Halmay, Hungarian swimmer who won seven Olympic medals and was the first world record holder in the 100-metre freestyle. At the 1900 Olympic Games in Paris, Halmay won silver medals in the 200-metre and 4,000-metre freestyle events and a bronze in the 1,000-metre freestyle. At the 1904

  • Halmstad (Sweden)

    Halmstad, town and port, capital of the län (county) of Halland, southwestern Sweden, on the eastern shore of the Kattegat, at the mouth of Nissan River. The town was founded at the beginning of the 14th century and often served as the meeting place of the rulers and delegates of the three northern

  • halo (atmospheric optical phenomenon)

    Halo, any of a wide range of atmospheric optical phenomena that result when the Sun or Moon shines through thin clouds composed of ice crystals. These phenomena may be due to the refraction of light that passes through the crystals, or the reflection of light from crystal faces, or a combination

  • Halo (electronic game)

    Halo, first-person shooter (played from the point of view of the shooter) electronic game developed by Bungie Studios and released in 2001 by the Microsoft Corporation for its Xbox console. Using state-of-the-art graphics, sophisticated genre improvements, and an array of weapons and vehicles,

  • halo (art)

    Halo, in art, radiant circle or disk surrounding the head of a holy person, a representation of spiritual character through the symbolism of light. In Hellenistic and Roman art the sun-god Helios and Roman emperors often appear with a crown of rays. Because of its pagan origin, the form was avoided

  • halo CME (astronomy)

    coronal mass ejection: Properties: …launched toward Earth are called halo CMEs because as they approach Earth, they appear larger than the Sun, making a “halo” of bright coronal emission completely around it.

  • halo complex (chemistry)

    coordination compound: Halo complexes: Probably the most widespread class of complexes involving anionic ligands is that of the complexes of the halide ions—i.e., the fluoride, chloride, bromide, and iodide ions. In addition to forming simple halide salts, such as sodium chloride and nickel difluoride (in which the…

  • halo effect (psychology)

    Halo effect, error in reasoning in which an impression formed from a single trait or characteristic is allowed to influence multiple judgments or ratings of unrelated factors. Research on the phenomenon of the halo effect was pioneered by American psychologist Edward L. Thorndike, who in 1920

  • halo Population II (astronomy)

    Milky Way Galaxy: Principal population types: …from the nearly spherical “halo Population II” system to the very thin “extreme Population I” system. Each subdivision was found to contain (though not exclusively) characteristic types of stars, and it was even possible to divide some of the variable-star types into subgroups according to their population subdivision. The…

  • halo, galactic (astronomy)

    Galactic halo, in astronomy, nearly spherical volume of thinly scattered stars, globular clusters of stars, and tenuous gas observed surrounding spiral galaxies, including the Milky Way—the galaxy in which the Earth is located. The roughly spherical halo of the Milky Way is thought to have a

  • Haloa (Greek festival)

    Demeter: …Demeter were the following: (1) Haloa, apparently derived from halōs (“threshing floor”), begun at Athens and finished at Eleusis, where there was a threshing floor of Triptolemus, her first priest and inventor of agriculture; it was held in the month Poseideon (December). (2) Chloia, the festival of the grain beginning…

  • Haloarcula marismortui (archaean)

    archaea: Characteristics of the archaea: Halophilic archaeans, which include Haloarcula marismortui, a model organism used in scientific research, are thought to have acquired the unique set of genes for the methylaspartate pathway via a process known as horizontal gene transfer, in which genes are passed from one species to another.

  • Halobacterium (archaea genus)

    bacteria: 16S rRNA analysis: The only photosynthetic archaeon, Halobacterium, has a completely different type of photosynthesis that does not use chlorophyll in large protein complexes to activate an electron, as in plants and bacteria. Rather, it uses a single protein, bacteriorhodopsin, in which light energy is absorbed by retinal, a form of vitamin…

  • halobutyl (chemistry)

    butyl rubber: …BIIR or CIIR (known as halobutyls). The properties of these polymers are similar to those of IIR, but they can be cured more rapidly and with different and smaller amounts of curative agents. As a result, BIIR and CIIR can be cocured more readily in contact with other elastomers making…

  • halocarbon (chemical compound)

    Halocarbon, any chemical compound of the element carbon and one or more of the halogens (bromine, chlorine, fluorine, iodine); two important subclasses of halocarbons are the chlorocarbons, containing only carbon and chlorine, and the fluorocarbons, containing only carbon and fluorine. Examples of

  • halocline (oceanography)

    Halocline, vertical zone in the oceanic water column in which salinity changes rapidly with depth, located below the well-mixed, uniformly saline surface water layer. Especially well developed haloclines occur in the Atlantic Ocean, in which salinities may decrease by several parts per thousand

  • Halocyprida (crustacean)

    crustacean: Annotated classification: Order Halocyprida Silurian to present; 5 pairs of postoral appendages; maxilla leglike; no eyes; marine. Suborder Cladocopina Silurian to present; only 3 pairs of postoral appendages; marine. Subclass Podocopa Order

  • haloform (chemistry)

    carbene: Formation.: Other haloforms, compounds conforming to the formula HCX3, in which X equals an atom of chlorine, bromine, or iodine, react in an equivalent way to form the corresponding dihalocarbenes.

  • haloform reaction (chemistry)

    aldehyde: α-Halogenation: This reaction is called the haloform reaction, because X3C− ions react with water or another acid present in the system to produce compounds of the form X3CH, which are called haloforms (e.g., CHCl3 is called chloroform).

  • halogen (chemical element group)

    Halogen, any of the six nonmetallic elements that constitute Group 17 (Group VIIa) of the periodic table. The halogen elements are fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At), and tennessine (Ts). They were given the name halogen, from the Greek roots hal- (“salt”) and -gen

  • halogen element (chemical element group)

    Halogen, any of the six nonmetallic elements that constitute Group 17 (Group VIIa) of the periodic table. The halogen elements are fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At), and tennessine (Ts). They were given the name halogen, from the Greek roots hal- (“salt”) and -gen

  • halogen lamp

    Halogen lamp, Incandescent lamp with a quartz bulb and a gas filling that includes a halogen. It gives brilliant light from a compact unit. The halogen combines with the tungsten evaporated from the hot filament to form a compound that is attracted back to the filament, thus extending the

  • halogen oxide (chemical compound)

    nitrogen group element: Variations in bonding capacity: The phosphorus oxyhalides, of general formula POX3, appear to be examples of this; their phosphorus–oxygen bonds are observed to be shorter and stronger than expected for ordinary single bonds.

  • halogenated hydrocarbon (chemical compound)

    Halocarbon, any chemical compound of the element carbon and one or more of the halogens (bromine, chlorine, fluorine, iodine); two important subclasses of halocarbons are the chlorocarbons, containing only carbon and chlorine, and the fluorocarbons, containing only carbon and fluorine. Examples of

  • halogenation (chemical reaction)

    aldehyde: α-Halogenation: An α-hydrogen of an aldehyde can be replaced by a chlorine (Cl), bromine (Br), or iodine (I) atom when the compound is treated with Cl2, Br2, or I2, respectively, either without a catalyst or in the presence of an acidic catalyst.

  • halogeton (plant species)

    Halogeton: One species, known as halogeton or saltlover (H. glomeratus), was introduced into Nevada about 1930 and is considered a noxious weed throughout much of the western United States. It is confined to salty semidesert lands, primarily in disturbed areas such as abandoned fields, abused ranges, and roadsides. The high…

  • Halogeton (plant genus)

    Halogeton, genus of nine species of weedy plants in the amaranth family (Amaranthaceae), native to southwestern Siberia and northwestern China. Halogeton species are mostly annual plants and are known for their ability to tolerate saline soils. Several are considered invasive species in areas

  • Haloid Company (American corporation)

    Xerox, major American corporation that was a pioneer in office technology, notably being the first to manufacture xerographic plain-paper copiers. Headquarters are in Norwalk, Connecticut. The company was founded in 1906 as the Haloid Company, a manufacturer and distributor of photographic paper.

  • Haloid Xerox Company (American corporation)

    Xerox, major American corporation that was a pioneer in office technology, notably being the first to manufacture xerographic plain-paper copiers. Headquarters are in Norwalk, Connecticut. The company was founded in 1906 as the Haloid Company, a manufacturer and distributor of photographic paper.

  • halon (chemical compound)

    Halon, chemical compound formerly used in firefighting. A halon may be any of a group of organohalogen compounds containing bromine and fluorine and one or two carbons. The effectiveness of halons in extinguishing fires arises from their action in interrupting chain reactions that propagate the

  • Halon 104 (chemical compound)

    Carbon tetrachloride, a colourless, dense, highly toxic, volatile, nonflammable liquid possessing a characteristic odour and belonging to the family of organic halogen compounds, used principally in the manufacture of dichlorodifluoromethane (a refrigerant and propellant). First prepared in 1839 by

  • Halonen, Tarja (president of Finland)

    Tarja Halonen, Finnish politician who served as president of Finland (2000–12), the first woman elected to that office. As a student at the University of Helsinki, Halonen served (1969–70) as social affairs secretary and general secretary of the National Union of Finnish Students. After earning a

  • haloperidol (drug)

    antipsychotic drug: This led to the compound haloperidol, a more powerful antipsychotic with relatively fewer side effects.

  • halophile (biology)

    archaea: Characteristics of the archaea: For example, halophilic archaea appear to be able to thrive in high-salt environments because they house a special set of genes encoding enzymes for a metabolic pathway that limits osmosis. That metabolic pathway, known as the methylaspartate pathway, represents a unique type of anaplerosis (the process of…

  • halophilic organism (biology)

    archaea: Characteristics of the archaea: For example, halophilic archaea appear to be able to thrive in high-salt environments because they house a special set of genes encoding enzymes for a metabolic pathway that limits osmosis. That metabolic pathway, known as the methylaspartate pathway, represents a unique type of anaplerosis (the process of…

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