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Herbert Marcus Powell
Herbert Marcus Powell 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. He coined the term clathrate A clathrate is a chemical substance consisting of a lattice that traps or contains molecules. The word ''clathrate'' is derived from the Latin (), meaning ‘with bars, latticed’. ... [...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 judges 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". Fellow, Fellowship of the Society, the oldest known scientific academy in continuous existence, is a significant honour. It has been awarded to many eminent scientists throughout history, including Isaac Newton (1672), Michael Faraday (1824), Charles Darwin (1839), Ernest Rutherford (1903), Srinivasa Ramanujan (1918), Albert Einstein (1921), Paul Dirac (1930), Winston Churchill (1941), Subrahmanyan Chandrasekhar (1944), Dorothy Hodgkin (1947), Alan Turing (1951), Lise Meitner (1955) and Francis Crick (1959). More recently, fellowship has been awarded to Stephen Hawking (1974), David Attenborough (1983), Tim Hunt (1991), Elizabeth Blackburn (1992), Tim Berners-Lee (2001), Venki R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Oxford
, mottoeng = The Lord is my light , established = , endowment = £6.1 billion (including colleges) (2019) , budget = £2.145 billion (2019–20) , chancellor = The Lord Patten of Barnes , vice_chancellor = Louise Richardson , students = 24,515 (2019) , undergrad = 11,955 , postgrad = 12,010 , other = 541 (2017) , city = Oxford , country = England , coordinates = , campus_type = University town , athletics_affiliations = Blue (university sport) , logo_size = 250px , website = , logo = University of Oxford.svg , colours = Oxford Blue , faculty = 6,995 (2020) , academic_affiliations = , The University of Oxford is a collegiate research university in Oxf ... [...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 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 give molecular ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Valence Electron
In chemistry and physics, a valence electron is an electron in the outer shell associated with an atom, and that can participate in the formation of a chemical bond if the outer 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 rel ... [...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 1775, when Henry Baker left £100 to establish a spoken lecture given by a Fellow of the Royal Society ''on such part of natural history or experimental philosophy'' as the Society shall determine. Clearly, this is to deliver a lecture of scientific interests and importance, and encourage sharing of knowledge with others. Awardees SourceRoyal Society 21st century *2023 Andrew Zisserman, ''for research on computational theory and commercial systems for geometrical analysis of images, and for being a pioneer and leading scientist in machine learning for vision, especially image recognition'' *202 ... [...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 researche ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
St John's College, Oxford
St John's College is a 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, intended to provide a source of educated Roman Catholic clerics to support the Counter-Reformation under Queen Mary. St John's is the wealthiest college in Oxford, with a financial endowment of £600 million as of 2020, 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' 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 score of 79.8. History On 1 May 1555, Sir Thomas White, lately Lord Mayor of London, obt ... [...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 British 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 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 her ... [...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 is known for its iconic bridge, 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. Alumni of the college's predecessor institutions include Will ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clathrate
A clathrate is a chemical substance consisting of a lattice that traps or contains molecules. The word ''clathrate'' is derived from the Latin (), meaning ‘with bars, 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 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 framework and guests that reside the framework. Most common clathrate crystal structures can be compos ... [...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 Majlis. * January 16–April 7 – The Algeciras Conference convenes, to resolve the First Moroccan Crisis between France and Germany. * January 22 – The strikes a reef off Vancouver Island, Canada, killing over 100 (officially 136) in the ensuing disaster. * January 31 – The Ecuador–Colombia earthquake (8.8 on the Moment magnitude scale), and associated tsunami, cause at least 500 deaths. * February 7 – is launched, sparking a naval race between Britain and Germany. * February 11 ** Pope Pius X publishes the encyclical ''Vehementer Nos'', denouncing the 1905 French law on the Separation of the Churches and the State. ** Two British members of a poll tax collecting ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1991 Deaths
File:1991 Events Collage.png, From left, clockwise: Boris Yeltsin, 1991 Russian presidential election, elected as Russia's first President of Russia, president, waves the new flag of Russia after the 1991 Soviet coup d'état attempt, orchestrated by Soviet Union, Soviet hardliners; Mount Pinatubo 1991 eruption of Mount Pinatubo, erupts in the Philippines, making it the List of large historical volcanic eruptions, second-largest Types of volcanic eruptions, volcanic eruption of the 20th century; MTS Oceanos sinks off the coast of South Africa, but the crew notoriously abandons the vessel before the passengers are rescued; Dissolution of the Soviet Union: The Flag of the Soviet Union, Soviet flag is lowered from the Kremlin for the last time and replaced with the flag of the Russian Federation; The United States and soon-to-be dissolved Soviet Union sign the START I Treaty; A tropical cyclone 1991 Bangladesh cyclone, strikes Bangladesh, killing nearly 140,000 people; Lauda Air Flight ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
