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Herbert Marcus Powell
Herbert Marcus Powell Fellow of the Royal Society, FRS (7 August 1906 – 10 March 1991) was a British chemist and professor at the University of Oxford. Powell presented the idea of a correlation between molecular geometry and number of valence electron pairs in a Bakerian Lecture in 1940 with Nevil Sidgwick on University of Oxford. He studied chemistry at St John's College, Oxford, graduating with First Class honours in 1928, then continued to work in the Chemistry department in Oxford throughout his career. Powell supervised some of Dorothy Crowfoot's undergraduate training in crystallography. In 1964 he became the first (and only) Professor of Chemical Crystallography, retiring from the university in 1974. He was not a fellow of any college until his 1963 appointment to Hertford College, Oxford, Hertford College. He coined the term clathrates for inclusion compounds. References {{DEFAULTSORT:Powell, Herbert Marcus 1906 births 1991 deaths British chemists Fellows of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fellow Of The Royal Society
Fellowship of the Royal Society (FRS, ForMemRS and HonFRS) is an award granted by the Fellows of the Royal Society of London to individuals who have made a "substantial contribution to the improvement of natural science, natural knowledge, including mathematics, engineering science, and medical science". Overview Fellowship of the Society, the oldest known scientific academy in continuous existence, is a significant honour. It has been awarded to :Fellows of the Royal Society, around 8,000 fellows, including eminent scientists Isaac Newton (1672), Benjamin Franklin (1756), Charles Babbage (1816), Michael Faraday (1824), Charles Darwin (1839), Ernest Rutherford (1903), Srinivasa Ramanujan (1918), Jagadish Chandra Bose (1920), Albert Einstein (1921), Paul Dirac (1930), Subrahmanyan Chandrasekhar (1944), Prasanta Chandra Mahalanobis (1945), Dorothy Hodgkin (1947), Alan Turing (1951), Lise Meitner (1955), Satyendra Nath Bose (1958), and Francis Crick (1959). More recently, fellow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Oxford
The University of Oxford is a collegiate university, collegiate research university in Oxford, England. There is evidence of teaching as early as 1096, making it the oldest university in the English-speaking world and the List of oldest universities in continuous operation, second-oldest continuously operating university globally. It expanded rapidly from 1167, when Henry II of England, Henry II prohibited English students from attending the University of Paris. When disputes erupted between students and the Oxford townspeople, some Oxford academics fled northeast to Cambridge, where they established the University of Cambridge in 1209. The two English Ancient university, ancient universities share many common features and are jointly referred to as ''Oxbridge''. The University of Oxford comprises 43 constituent colleges, consisting of 36 Colleges of the University of Oxford, semi-autonomous colleges, four permanent private halls and three societies (colleges that are depar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular Geometry
Molecular geometry is the three-dimensional arrangement of the atoms that constitute a molecule. It includes the general shape of the molecule as well as bond lengths, bond angles, torsional angles and any other geometrical parameters that determine the position of each atom. Molecular geometry influences several properties of a substance including its reactivity, polarity, phase of matter, color, magnetism and biological activity. The angles between bonds that an atom forms depend only weakly on the rest of a molecule, i.e. they can be understood as approximately local and hence transferable properties. Determination The molecular geometry can be determined by various spectroscopic methods and diffraction methods. IR, microwave and Raman spectroscopy can give information about the molecule geometry from the details of the vibrational and rotational absorbance detected by these techniques. X-ray crystallography, neutron diffraction and electron diffraction can g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Valence Electron
In chemistry and physics, valence electrons are electrons in the outermost shell of an atom, and that can participate in the formation of a chemical bond if the outermost shell is not closed. In a single covalent bond, a shared pair forms with both atoms in the bond each contributing one valence electron. The presence of valence electrons can determine the element's chemical properties, such as its valence—whether it may bond with other elements and, if so, how readily and with how many. In this way, a given element's reactivity is highly dependent upon its electronic configuration. For a main-group element, a valence electron can exist only in the outermost electron shell; for a transition metal, a valence electron can also be in an inner shell. An atom with a closed shell of valence electrons (corresponding to a noble gas configuration) tends to be chemically inert. Atoms with one or two valence electrons more than a closed shell are highly reactive due to the relativ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bakerian Lecture
The Bakerian Medal is one of the premier medals of the Royal Society that recognizes exceptional and outstanding science. It comes with a medal award and a prize lecture. The medalist is required to give a lecture on any topic related to physical sciences. It is awarded annually to individuals in the field of physical sciences, including computer science. History The prize was started in 1774, when Henry Baker left £100 to establish a spoken lecture given by a Fellow of the Royal Society about natural history or experimental philosophy. Awardees Source: 21st century * 2025 Ingrid Daubechies, ''for her outstanding work on wavelets and image compression and her exceptional contributions to a wide spectrum of physical, technological, and mathematical applications'' * 2024 Michele Dougherty, ''for her scientific leadership of the Cassini magnetic field instrument at Saturn, seminal research findings on potential life support on Enceladus and leadership of forthcoming missions t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nevil Sidgwick
Nevil Vincent Sidgwick FRS (8 May 1873 – 15 March 1952) was an English theoretical chemist who made significant contributions to the theory of valency and chemical bonding. Biography Sidgwick was born in Park Town, Oxford, the elder of two children of William Carr Sidgwick, lecturer at Oriel College, and Sarah Isabella (née Thompson), descended from a notable family; her uncle was Thomas Perronet Thompson. He was initially educated at Summer Fields School but, after a year, he entered Rugby School in 1886. From there he was elected to an open scholarship in Natural Science at Christ Church, Oxford. He gained a first in 1895, and went on to gain another first in Greats in 1897, a very rare feat. His principal interest, though, was science, and he spent some time in Wilhelm Ostwald’s laboratory in Germany, where he fell ill and had to go home. He returned to Germany in the autumn of 1899, this time in Hans von Pechmann’s lab at the University of Tübingen. His researc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
St John's College, Oxford
St John's College is a Colleges of the University of Oxford, constituent college of the University of Oxford. Founded as a men's college in 1555, it has been coeducational since 1979.Communication from Michael Riordan, college archivist Its founder, Sir Thomas White (merchant), Thomas White, intended to provide a source of educated Roman Catholic clerics to support the Counter-Reformation under Mary I of England, Queen Mary. St John's is the wealthiest college in Oxford, with assets worth over £790 million as of 2022, largely due to nineteenth-century suburban development of land in the city of Oxford of which it is the ground landlord. The college occupies a site on St Giles', Oxford, St Giles' and has a student body of some 390 undergraduates and 250 postgraduates. There are over 100 academic staff, and a like number of other staff. In 2018 St John's topped the Norrington Table, the annual ranking of Oxford colleges' final results, and in 2021, St John's ranked second with a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dorothy Crowfoot
Dorothy Mary Crowfoot Hodgkin (née Crowfoot; 12 May 1910 – 29 July 1994) was a Nobel Prize-winning English chemist who advanced the technique of X-ray crystallography to determine the structure of biomolecules, which became essential for structural biology. Among her most influential discoveries are the confirmation of the structure of penicillin as previously surmised by Edward Abraham and Ernst Boris Chain; and mapping the structure of vitamin B12, for which in 1964 she became the third woman to win the Nobel Prize in Chemistry. Hodgkin also elucidated the structure of insulin in 1969 after 35 years of work. Hodgkin used the name "Dorothy Crowfoot" until twelve years after marrying Thomas Lionel Hodgkin, when she began using "Dorothy Crowfoot Hodgkin". Hodgkin is referred to as "Dorothy Hodgkin" by the Royal Society (when referring to its sponsorship of the Dorothy Hodgkin fellowship), and by Somerville College. The National Archives of the United Kingdom refer to h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hertford College, Oxford
Hertford College ( ), previously known as Magdalen Hall, is a colleges of the University of Oxford, constituent college of the University of Oxford in England. It is located on Catte Street in the centre of Oxford, directly opposite the main gate to the Bodleian Library. The college’s Old and New Quadrangles are connected by the Bridge of Sighs (Oxford), Bridge of Sighs. There are around 600 students at the college at any one time, comprising undergraduates, graduates and visiting students from overseas. The first foundation on the Hertford site began in the 1280s as Hart Hall and became a college in 1740 but was dissolved in 1816. In 1820, the site was taken over by Magdalen Hall, which had emerged around 1490 on a site adjacent to Magdalen College. In 1874, Magdalen Hall was incorporated as a college, reviving the name Hertford College. In 1974, Hertford was part of the first group of all-male Oxford colleges to admit women. Hertford College specialises in both Irish studi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clathrate
A clathrate is a chemical substance consisting of a lattice (group), lattice that traps or contains molecules. The word ''clathrate'' is derived from the Latin language, Latin (), meaning 'with bars, Crystal structure, latticed'. Most clathrate compounds are polymeric and completely envelop the guest molecule, but in modern usage clathrates also include host–guest complexes and inclusion compounds.Atwood, J. L. (2012) "Inclusion Compounds" in ''Ullmann's Encyclopedia of Industrial Chemistry''. Wiley-VCH, Weinheim. According to International Union of Pure and Applied Chemistry, IUPAC, clathrates are inclusion compounds "in which the guest molecule is in a cage formed by the host molecule or by a lattice of host molecules." The term refers to many molecular hosts, including calixarenes and cyclodextrins and even some inorganic polymers such as zeolites. Clathrates can be divided into two categories: clathrate hydrates and inorganic clathrates. Each clathrate is made up of a fram ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1906 Births
Events January–February * January 12 – Persian Constitutional Revolution: A nationalistic coalition of merchants, religious leaders and intellectuals in Persia forces the shah Mozaffar ad-Din Shah Qajar to grant a constitution, and establish a national assembly, the National Consultative Assembly, Majlis. * January 16–April 7 – The Algeciras Conference convenes, to resolve the First Moroccan Crisis between French Third Republic, France and German Empire, Germany. * January 22 – The strikes a reef off Vancouver Island, Canada, killing over 100 (officially 136) in the ensuing disaster. * January 31 – The 1906 Ecuador–Colombia earthquake, Ecuador–Colombia earthquake (8.8 on the Moment magnitude scale), and associated tsunami, cause at least 500 deaths. * February 7 – is launched, sparking a Anglo-German naval arms race, naval race between Britain and Germany. * February 11 ** Pope Pius X publishes the encyclical ''Vehementer Nos'', de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1991 Deaths
This is a list of lists of deaths of notable people, organized by year. New deaths articles are added to their respective month (e.g., Deaths in ) and then linked below. 2025 2024 2023 2022 2021 2020 2019 2018 2017 2016 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995 1994 1993 1992 1991 1990 1989 1988 1987 1986 Earlier years ''Deaths in years earlier than this can usually be found in the main articles of the years.'' See also * Lists of deaths by day * Deaths by year (category) {{DEFAULTSORT:deaths by year ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
