In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula −OH and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or more hydroxy groups. Both the negatively charged anion HO−, called hydroxide, and the neutral radical HO·, known as the hydroxyl radical, consist of an unbonded hydroxy group.
According to IUPAC definitions, the term hydroxyl refers to the hydroxyl radical (·OH) only, while the functional group −OH is called a hydroxy group.[1]
Water, alcohols, carboxylic acids, and many other hydroxy-containing compounds can be readily deprotonated due to a large difference between the electronegativity of oxygen (3.5) and that of hydrogen (2.1). Hydroxy-containing compounds engage in intermolecular hydrogen bonding increasing the electrostatic attraction between molecules and thus to higher boiling and melting points than found for compounds that lack this functional group. Organic compounds, which are often poorly soluble in water, become water-soluble when they contain two or more hydroxy groups, as illustrated by sugars and amino acid.[citation needed]
The hydroxy group is pervasive in chemistry and biochemistry. Many inorganic compounds contain hydroxyl groups, including sulfuric acid, the chemical compound produced on the largest scale industrially.[2]
Hydroxy groups participate in the dehydration reactions that link simple biological molecules into long chains. The joining of a fatty acid to glycerol to form a triacylglycerol removes the −OH from the carboxy end of the fatty acid. The joining of two aldehyde sugars to form a disaccharide removes the −OH from the carboxy group at the aldehyde end of one sugar. The creation of a peptide bond to link two amino acids to make a protein removes the −OH from the carboxy group of one amino acid.[citation needed]
Hydroxyl radicals are highly reactive and undergo chemical reactions that make them short-lived. When biological systems are exposed to hydroxyl radicals, they can cause damage to cells, including those in humans, where they can react with DNA, lipids, and proteins.[3]
The Earth's night sky is illuminated by diffuse light, called airglow, that is produced by radiative transitions of atoms and molecules.[4] Among the most intense such features observed in the Earth's night sky is a group of infrared transitions at wavelengths between 700 nanometers and 900 nanometers. In 1950, Aden Meinel showed that these were transitions of the hydroxyl molecule, OH.[5]
In 2009, India's Chandrayaan-1 satellite and the National Aeronautics and Space Administration (NASA) Cassini spacecraft and Deep Impact probe each detected evidence of water by evidence of hydroxyl fragments on the Moon. As reported by Richard Kerr, "A spectrometer [the Moon Mineralogy Mapper, also known as "M3"] detected an infrared absorption at a wavelength of 3.0 micrometers that only water or hydroxyl—a hydrogen and an oxygen bound together—could have created."[6] NASA also reported in 2009 that the LCROSS probe revealed an ultraviolet emission spectrum consistent with hydroxyl presence.[7]
On 26 October 2020, NASA reported definitive evidence of water on the sunlit surface of the Moon, in the vicinity of the crater Clavius (crater), obtained by the Stratospheric Observatory for Infrared Astronomy (SOFIA).[8] The SOFIA Faint Object infrared Camera for the SOFIA Telescope (FORCAST) detected emission bands at a wavelength of 6.1 micrometers that are present in water but not in hydroxyl. The abundance of water on the Moon's surface was inferred to be equivalent to the contents of a 12-ounce bottle of water per cubic meter of lunar soil.[9]
The Chang'e 5 probe, which landed on the Moon on 1 December 2020, carried a mineralogical spectrometer that could measure infrared reflectance spectra of lunar rock and regolith. The reflectance spectrum of a rock sample at a wavelength of 2.85 micrometers indicated localized water/hydroxyl concentrations as high as 180 parts per million.[10]
The Venus Express orbiter collected Venus science data from April 2006 until December 2014. In 2008, Piccioni, et al. reported measurements of night-side airglow emission in the atmosphere of Venus made with the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) on Venus Express. They attributed emission bands in wavelength ranges of 1.40 - 1.49 micrometers and 2.6 - 3.14 micrometers to vibrational transitions of OH.[11] This was the first evidence for OH in the atmosphere of any planet other than Earth's.[11]
In 2013, OH near-infrared spectra were observed in the night glow in the polar winter atmosphere of Mars by use of the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM).[12]
In 2021, evidence for OH in the dayside atmosphere of the exoplanet WASP-33b was found in its emission spectrum at wavelengths between 1 and 2 micrometers.[13] Evidence for OH in the atmosphere of exoplanet WASP-76b was subsequently found.[14] Both WASP-33b and WASP-76b are ultra-hot Jupiters and it is likely that any water in their atmospheres is present as dissociated ions.
Legare Rogers LyttonLytton pada 1921LahirOscar Legare Rogers(1867-04-09)9 April 1867New Orleans, Louisiana, Amerika SerikatMeninggal14 Agustus 1924(1924-08-14) (umur 57)New York City, Amerika SerikatAlmamaterUniversitas ColumbiaPekerjaanPemeran, arsitekTahun aktif1912–1924 Legare Rogers Lytton[1] (nama lahir Oscar Legare Rogers;[2] 9 April 1867 – 14 Agustus 1924) adalah seorang pemeran film Amerika Serikat pada era film bisu dan arsitek.[1] Ia …
Marianne Fundahn Marianne Fundahn i riksdagen. Ledamot av Sveriges riksdag Mandatperiod2014–2018 (ersättare)2018–20222022–2026 Valkrets Skåne läns södra Uppdrag i riksdagen Suppleant i ArbetsmarknadsutskottetSuppleant i SocialförsäkringsutskottetSuppleant i Socialutskottet Född 1 november 1958 (65 år)Rängs församling, Malmöhus län Politiskt parti Socialdemokraterna Yrke undersköterska Carina Marianne Fundahn, tidigare Pettersson,[1] född 1 november 1958 i …
Ron SexsmithRon Sexsmith en 2011BiographieNaissance 8 janvier 1964 (59 ans)Saint CatharinesNationalité canadienneDomiciles Toronto, Saint CatharinesActivités Auteur-compositeur-interprète, musicien, auteur-compositeur, chanteur, pianistePériode d'activité depuis 1978Autres informationsInstruments Piano, guitareLabel Warner Bros. Records (en)Genres artistiques Pop, folkSite web (en) ronsexsmith.comDistinctions Prix Juno de l'album de musique roots et traditionnelle de l'année …
Тім Агаба(англ. Tim Agaba)Загальна інформаціяГромадянство ПАРНародження 23 липня 1989(1989-07-23) (34 роки)Кампала, УгандаЗріст 193 смВага 106 кгAlma mater Nelson Mandela Universityd і Університет Південної АфрикиdСпортКраїна ПАРВид спорту регбіКоманда South Africa national rugby sevens teamd Участь і здобутки Наг
Privat-Brauerei Strate Detmold Rechtsform GmbH & Co. KG Gründung 1863 Sitz Detmold Leitung Renate, Simone und Friederike Strate Mitarbeiterzahl 33 Branche Brauerei Website www.brauerei-strate.de Detmolder Landbier Die Privat-Brauerei Strate Detmold GmbH & Co. KG ist eine Brauerei in Detmold im Kreis Lippe. Inhaltsverzeichnis 1 Geschichte 2 Biersorten 3 Sonstiges 4 Einzelnachweise 5 Weblinks Geschichte Die Brauerei wurde 1863 von Adolf Hüppe gegründet. Der Sitz der Brauerei war damals …
يفتقر محتوى هذه المقالة إلى الاستشهاد بمصادر. فضلاً، ساهم في تطوير هذه المقالة من خلال إضافة مصادر موثوق بها. أي معلومات غير موثقة يمكن التشكيك بها وإزالتها. (مارس 2020) تشكيلات فرق كأس آسيا 2000 التي أقيمت في لبنان في الفترة من 12 أكتوبر إلى 29 أكتوبر 2000. المجموعة أ إيران المدرب: جلا…
دوري الدرجة الأولى الأرجنتيني 1930 تفاصيل الموسم دوري الدرجة الأولى الأرجنتيني النسخة 50 البلد الأرجنتين التاريخ بداية:23 مارس 1930 المنظم اتحاد الأرجنتين لكرة القدم البطل بوكا جونيورز مباريات ملعوبة 630 عدد المشاركين 36 دوري الدرجة الأولى الأرجنتيني 192…
French road bicycle racer Pierre RollandRolland at the 2013 Critérium du DauphinéPersonal informationFull namePierre RollandBorn (1986-10-10) 10 October 1986 (age 37)Gien, FranceHeight1.84 m (6 ft 1⁄2 in)[1]Weight67 kg (148 lb; 10 st 8 lb)[1]Team informationCurrent teamRetiredDisciplineRoadRoleRiderRider typeClimberAmateur teams2005–2006Super Sport 352006Crédit Agricole (stagiaire) Professional teams2007–2008Cré…
Season of television series Yu-Gi-Oh! Arc-VSeason 2Yuya Sakaki(left) with Jean-Michel Roget (Right)Country of originJapanNo. of episodes50ReleaseOriginal networkTV TokyoOriginal releaseApril 5, 2015 (2015-04-05) –April 3, 2016 (2016-04-03)Season chronology← PreviousSeason 1Next →Season 3List of episodes Yu-Gi-Oh! Arc-V is the fourth spin-off anime in the Yu-Gi-Oh! franchise and the eighth anime series overall. It is produced by Nihon Ad Systems and broadcast by TV …
Para otros usos de este término, véase Ilo (desambiguación). IloSan Gerónimo de Ilo Ciudad Ilo BanderaEscudo IloLocalización de Ilo en Perú IloLocalización de Ilo en Moquegua Coordenadas 17°38′55″S 71°19′50″O / -17.648611111111, -71.330555555556Entidad Ciudad • País Perú Perú • Departamento Moquegua • Provincia IloAlcalde Humberto Tapia GarayFundación 21 de agosto de 1548 • Nombre San Gerónimo de YloSuperficie • Tota…
Cet article est une ébauche concernant la géographie et la Pologne. Vous pouvez partager vos connaissances en l’améliorant (comment ?) selon les recommandations des projets correspondants. Pour les articles homonymes, voir Tarnobrzeg (homonymie). Powiat de Tarnobrzeg Powiat tarnobrzeski Héraldique Drapeau Administration Pays Pologne Voïvodie Basses-Carpates Capitale Tarnobrzeg Starosta Krzysztof Pitra Plaque d'immatriculation RTA Démographie Population 54 256 hab. (2012) D…
Temporary ocean surface current Angola current is a temporary ocean surface current. It is an extension of the Guinea Current, flowing near western Africa's coast. It is known to have created similar effects in the upwelling as El Niño,[1] though its effect is weaker. See also Ocean current Oceanic gyres References ^ The Angola Current. vteOcean currents and gyresCurrentsArctic Ocean East Greenland North Icelandic Norwegian Transpolar Drift Stream Atlantic Ocean Angola Antilles Azores B…
Kreisklinikum für Notfallmedizin Timișoara Logo Trägerschaft Kreisrat Timiș (rumänisch: Consiliul Județean Timiș) Ort Timișoara Bundesland Kreis Timiș Staat Rumänien Koordinaten 45° 44′ 14″ N, 21° 14′ 34″ O45.737321.2428Koordinaten: 45° 44′ 14″ N, 21° 14′ 34″ O Klinikleiter Florin Bîrsăşteanu Betten 1030 Fachgebiete Anästhesie, Intensivtherapie, Chirurgie, Hämatologie, Innere Medizin, Notaufnahme, Radi…
هيئة البحوث الأسترالية الاختصار (بالإنجليزية: CSIRO) البلد أستراليا المقر الرئيسي كانبرا تاريخ التأسيس 1926[1]، و19 مايو 1949 العضوية أورسيد [لغات أخرى][2][3]، ورابطة الشبكة العالمية[4] الموقع الرسمي الموقع الرسمي[5] تعديل م…
Fish eaten by humans This article is about fish as food for humans. For sealife in general as food, see seafood. For fish fed to other fish, see commercial fish feed and aquarium fish feed. Channa striata stuffed with Thai herbs Fish for sale in baskets at the Dubai Fish Market Many species of fish are caught by humans and consumed as food in virtually all regions around the world. Fish has been an important dietary source of protein and other nutrients throughout human history. The English lang…
Village in Chūbu, JapanUrugi 売木村VillageUrugi Village Hall FlagSealLocation of Urugi in Nagano PrefectureUrugi Coordinates: 35°16′15.8″N 137°42′40.3″E / 35.271056°N 137.711194°E / 35.271056; 137.711194CountryJapanRegionChūbu (Kōshin'etsu)PrefectureNaganoDistrictShimoinaArea • Total43.43 km2 (16.77 sq mi)Population (April 2019) • Total552 • Density13/km2 (33/sq mi)Time zoneUTC+9 (Japan St…
Region (mkhare) of Georgia This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.Find sources: Racha-Lechkhumi and Kvemo Svaneti – news · newspapers · books · scholar · JSTOR (February 2022) (Learn how and when to remove this template message) Mkhare in GeorgiaRacha-Lechkhumi and Kvemo Svaneti რაჭა-ლეჩხუმი …
Namibian government department Politics of Namibia Constitution Constituent Assembly Executive President Hage Geingob Vice-President Nangolo Mbumba Prime Minister Saara Kuugongelwa Cabinet Legislature National Council Chairman: Bernard Sibalatani National Assembly Speaker: Peter Katjavivi Judiciary Supreme Court Chief Justice: Peter Shivute Administrative divisions Regions Constituencies Elections Recent elections General: 201420192024 Regional: 201020152020 Political parties Foreign relations M…
Hungarian physician and politician László KovácsMember of the National AssemblyIn office2 May 1990 – 27 June 1994 Personal detailsBorn(1941-03-27)27 March 1941Tapolca, HungaryDied5 December 2001(2001-12-05) (aged 60)Százhalombatta, HungaryPolitical partyMDFProfessionX-ray physician, politician The native form of this personal name is dr. Kovács László. This article uses Western name order when mentioning individuals. Dr. László Kovács (March 27, 1941 – December 5,…
Parliamentary constituency in the United Kingdom, 1885–1918 LewishamFormer Borough constituencyfor the House of CommonsLewisham in London1885–1918SeatsoneCreated fromWest KentReplaced byLewisham East and Lewisham West Lewisham was a borough constituency in the Lewisham district of London. It returned one Member of Parliament (MP) to the House of Commons of the Parliament of the United Kingdom, elected by the first past the post system. History The constituency was created by the Redistributi…
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