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[1] [2] [3] Introduced by Gilbert N. Lewis in his 1916 article The Atom and the Molecule, a Lewis structure can be drawn for any covalently bonded molecule, as well as coordination compounds. [4] Lewis structures extend the concept of the electron dot diagram by adding lines between atoms to represent shared pairs in a chemical bond.
In a Lewis adduct, the Lewis acid and base share an electron pair furnished by the Lewis base, forming a dative bond. [1] In the context of a specific chemical reaction between NH 3 and Me 3 B, a lone pair from NH 3 will form a dative bond with the empty orbital of Me 3 B to form an adduct NH 3 •BMe 3 .
3) are very useful synthetic intermediates in the production of more complicated silicon-containing compounds: the latter is a colourless crystalline ionic solid containing K + cations and SiH − 3 anions in the NaCl structure, and is made by the reduction of silane by potassium metal. [9] Additionally, the reactive hypervalent species SiH −
Again there is variation in composition: magnesium silicide is represented by Mg 2 Si, [9] calcium silicide can be represented by Ca 2 Si, CaSi, CaSi 2, Ca 5 Si 3 and by Ca 14 Si 19, [10] strontium silicide can be represented by Sr 2 Si, SrSi 2 and Sr 5 Si 3 [11] and barium silicide can be represented by Ba 2 Si, BaSi 2, Ba 5 Si 3 and Ba 3 Si 4 ...
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Silicon–oxygen single bonds are longer (1.6 vs 1.4 Å) but stronger (452 vs. about 360 kJ mol −1) than carbon–oxygen single bonds. [1] However, silicon–oxygen double bonds are weaker than carbon–oxygen double bonds (590 vs. 715 kJ mol −1 ) due to a better overlap of p orbitals forming a stronger pi bond in the latter.
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Common Lewis acid catalysts are based on main group metals such as aluminum, boron, silicon, and tin, as well as many early (titanium, zirconium) and late (iron, copper, zinc) d-block metals. The metal atom forms an adduct with a lone-pair bearing electronegative atom in the substrate, such as oxygen (both sp 2 or sp 3), nitrogen, sulfur, and ...