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Alkaline Earth Octacarbonyl Complex
Alkaline earth octacarbonyl complexes are a class of neutral compounds that have the general formula M(CO)8 where M is a heavy Group 2 element ( Ca, Sr, or Ba). The metal center has a formal oxidation state of 0 and the complex has a high level of symmetry belonging to the cubic ''Oh'' point group. These complexes are isolable in a low-temperature neon matrix, but are not frequently used in applications due to their instability in air and water. The bonding within these complexes is controversial with some arguing the bonding resembles a model similar to bonding in transition metal carbonyl complexes which abide by the 18-electron rule, and others arguing the molecule more accurately contains ionic bonds between the alkaline earth metal center and the carbonyl ligands. Complexes of Be(CO)8 and Mg(CO)8 are not synthetically possible due to inaccessible (n-1)d orbitals. Beryllium has been found to form a dinuclear homoleptic carbonyl and magnesium a mononuclear heteroleptic ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
M(CO)8
M, or m, is the thirteenth letter in the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is ''em'' (pronounced ), plural ''ems''. History The letter M is derived from the Phoenician Mem, via the Greek Mu (Μ, μ). Semitic Mem is most likely derived from a " Proto-Sinaitic" (Bronze Age) adoption of the "water" ideogram in Egyptian writing. The Egyptian sign had the acrophonic value , from the Egyptian word for "water", ''nt''; the adoption as the Semitic letter for was presumably also on acrophonic grounds, from the Semitic word for "water", '' *mā(y)-''. Use in writing systems The letter represents the bilabial nasal consonant sound in the orthography of Latin as well as in that of many modern languages, and also in the International Phonetic Alphabet. In English, the Oxford English Dictionary (first edition) says that is sometimes a vowel, in words like ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infrared Spectroscopy
Infrared spectroscopy (IR spectroscopy or vibrational spectroscopy) is the measurement of the interaction of infrared radiation with matter by absorption, emission, or reflection. It is used to study and identify chemical substances or functional groups in solid, liquid, or gaseous forms. It can be used to characterize new materials or identify and verify known and unknown samples. The method or technique of infrared spectroscopy is conducted with an instrument called an infrared spectrometer (or spectrophotometer) which produces an infrared spectrum. An IR spectrum can be visualized in a graph of infrared light absorbance (or transmittance) on the vertical axis vs. frequency, wavenumber or wavelength on the horizontal axis. Typical units of wavenumber used in IR spectra are reciprocal centimeters, with the symbol cm−1. Units of IR wavelength are commonly given in micrometers (formerly called "microns"), symbol μm, which are related to the wavenumber in a reciprocal way. A com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lewis Acids And Bases
A Lewis acid (named for the American physical chemist Gilbert N. Lewis) is a chemical species that contains an empty orbital which is capable of accepting an electron pair from a Lewis base to form a Lewis adduct. A Lewis base, then, is any species that has a filled orbital containing an electron pair which is not involved in bonding but may form a dative bond with a Lewis acid to form a Lewis adduct. For example, NH3 is a Lewis base, because it can donate its lone pair of electrons. Trimethylborane (Me3B) is a Lewis acid as it is capable of accepting a lone pair. In a Lewis adduct, the Lewis acid and base share an electron pair furnished by the Lewis base, forming a dative bond. In the context of a specific chemical reaction between NH3 and Me3B, a lone pair from NH3 will form a dative bond with the empty orbital of Me3B to form an adduct NH3•BMe3. The terminology refers to the contributions of Gilbert N. Lewis. From p. 142: "We are inclined to think of substances as pos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MO Of M(CO)8 Alkaline
Mo or MO may refer to: Arts and entertainment Fictional characters * Mo, a girl in the '' Horrible Histories'' TV series * Mo, also known as Mortimer, in the novel '' Inkheart'' by Cornelia Funke * Mo, in the webcomic ''Jesus and Mo'' * Mo, the main character in the ''Mo's Mischief'' children's book series * Mo, an ophthalmosaurus from ''The Land Before Time'' franchise * MO (Maintenance Operator), a robot in the Filmation series '' Young Sentinels'' * Mo, a main character in '' Zoey's Extraordinary Playlist'' * M-O (Microbe Obliterator), a robot in film '' WALL-E'' * Mo the clown, a character played by Roy Rene, 20th-century Australian stage comedian * Mo Effanga, in the BBC medical drama series ''Holby City'' * Mo Harris, in the BBC soap opera ''EastEnders'' * Little Mo Mitchell, in the BBC soap opera ''EastEnders'' Films * "Mo" (魔 demon), original title of ''The Boxer's Omen'', a 1983 Hong Kong film * ''Mo'' (2010 film), a television movie about British politician Mo Mow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transition Metal
In chemistry, a transition metal (or transition element) is a chemical element in the d-block of the periodic table (groups 3 to 12), though the elements of group 12 (and less often group 3) are sometimes excluded. They are the elements that can use d orbitals as valence orbitals to form chemical bonds. The lanthanide and actinide elements (the f-block) are called inner transition metals and are sometimes considered to be transition metals as well. Since they are metals, they are lustrous and have good electrical and thermal conductivity. Most (with the exception of group 11 and group 12) are hard and strong, and have high melting and boiling temperatures. They form compounds in any of two or more different oxidation states and bind to a variety of ligands to form coordination complexes that are often coloured. They form many useful alloys and are often employed as catalysts in elemental form or in compounds such as coordination complexes and oxides. Most are strongly param ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Density Functional Theory
Density-functional theory (DFT) is a computational quantum mechanical modelling method used in physics, chemistry and materials science to investigate the electronic structure (or nuclear structure) (principally the ground state) of many-body systems, in particular atoms, molecules, and the condensed phases. Using this theory, the properties of a many-electron system can be determined by using functionals, i.e. functions of another function. In the case of DFT, these are functionals of the spatially dependent electron density. DFT is among the most popular and versatile methods available in condensed-matter physics, computational physics, and computational chemistry. DFT has been very popular for calculations in solid-state physics since the 1970s. However, DFT was not considered accurate enough for calculations in quantum chemistry until the 1990s, when the approximations used in the theory were greatly refined to better model the exchange and correlation interactions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dewar–Chatt–Duncanson Model
The Dewar–Chatt–Duncanson model is a model in organometallic chemistry that explains the chemical bonding in transition metal alkene complexes. The model is named after Michael J. S. Dewar, Joseph Chatt and L. A. Duncanson. The alkene donates electron density into a π-acid metal d-orbital from a π-symmetry bonding orbital between the carbon atoms. The metal donates electrons back from a (different) filled d-orbital into the empty π* antibonding orbital. Both of these effects tend to reduce the carbon-carbon bond order, leading to an elongated C−C distance and a lowering of its vibrational frequency. In Zeise's salt K platinum">PtCl3(C2H4).html" ;"title="platinum.html" ;"title="/nowiki>platinum">PtCl3(C2H4)">platinum.html" ;"title="/nowiki>platinum">PtCl3(C2H4)sup>.H2O the C−C bond length has increased to 134 picometres from 133 pm for ethylene. In the nickel compound Ni(C2H4)(PPh3)2 the value is 143 pm. The interaction also causes carbon atoms to "rehybridise" from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Octet Rule
The octet rule is a chemical rule of thumb that reflects the theory that main-group elements tend to bond in such a way that each atom has eight electrons in its valence shell, giving it the same electronic configuration as a noble gas. The rule is especially applicable to carbon, nitrogen, oxygen, and the halogens; although more generally the rule is applicable for the s-block and p-block of the periodic table. Other rules exist for other elements, such as the duplet rule for hydrogen and helium, or the 18-electron rule for transition metals. The valence electrons can be counted using a Lewis electron dot diagram as shown at the right for carbon dioxide. The electrons shared by the two atoms in a covalent bond are counted twice, once for each atom. In carbon dioxide each oxygen shares four electrons with the central carbon, two (shown in red) from the oxygen itself and two (shown in black) from the carbon. All four of these electrons are counted in both the carbon octet and the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electron Configuration
In atomic physics and quantum chemistry, the electron configuration is the distribution of electrons of an atom or molecule (or other physical structure) in atomic or molecular orbitals. For example, the electron configuration of the neon atom is , meaning that the 1s, 2s and 2p subshells are occupied by 2, 2 and 6 electrons respectively. Electronic configurations describe each electron as moving independently in an orbital, in an average field created by all other orbitals. Mathematically, configurations are described by Slater determinants or configuration state functions. According to the laws of quantum mechanics, for systems with only one electron, a level of energy is associated with each electron configuration and in certain conditions, electrons are able to move from one configuration to another by the emission or absorption of a quantum of energy, in the form of a photon. Knowledge of the electron configuration of different atoms is useful in understanding the structu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Three M(CO)8
3 is a number, numeral, and glyph. 3, three, or III may also refer to: * AD 3, the third year of the AD era * 3 BC, the third year before the AD era * March, the third month Books * ''Three of Them'' (Russian: ', literally, "three"), a 1901 novel by Maksim Gorky * ''Three'', a 1946 novel by William Sansom * ''Three'', a 1970 novel by Sylvia Ashton-Warner * ''Three'' (novel), a 2003 suspense novel by Ted Dekker * ''Three'' (comics), a graphic novel by Kieron Gillen. * ''3'', a 2004 novel by Julie Hilden * ''Three'', a collection of three plays by Lillian Hellman * ''Three By Flannery O'Connor'', collection Flannery O'Connor bibliography Brands * 3 (telecommunications), a global telecommunications brand ** 3Arena, indoor amphitheatre in Ireland operating with the "3" brand ** 3 Hong Kong, telecommunications company operating in Hong Kong ** Three Australia, Australian telecommunications company ** Three Ireland, Irish telecommunications company ** Three UK, British telec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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