Search results
Results From The WOW.Com Content Network
It is more hydrogen-dense than liquid hydrogen and also able to exist at normal temperatures and pressures. [17] Ammonia borane finds some use in organic synthesis as an air-stable derivative of diborane. [18] It can be used as a reducing agent in transfer hydrogenation reactions, often in the presence of a transition metal catalyst. [19]
The reaction commences with the formation of the aquo adduct, H 2 O−BF 3, which then loses HF that gives fluoroboric acid with boron trifluoride. [22] 4 BF 3 + 3 H 2 O → 3 H[BF 4] + B(OH) 3. The heavier trihalides do not undergo analogous reactions, possibly due to the lower stability of the tetrahedral ions [BCl 4] − and [BBr 4] −.
[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.
Borane ammoniate, which is produced by a displacement reaction of other borane adducts, eliminates elemental hydrogen on heating to give borazine (HBNH) 3. [12] Borane adducts are widely used in organic synthesis for hydroboration, where BH 3 adds across the C=C bond in alkenes to give trialkylboranes: [13] (THF)BH 3 + 3 CH 2 =CHR → B(CH 2 CH ...
The dot-and-cross diagram of the LDQ structure of the ground state of acetylene is shown on the left and that of the first excited state of acetylene is shown on the right. The nuclei are as indicated and the electrons are denoted by either dots or crosses, depending on their relative spins.
The interaction also causes carbon atoms to "rehybridise" from sp 2 towards sp 3, which is indicated by the bending of the hydrogen atoms on the ethylene back away from the metal. [4] In silico calculations show that 75% of the binding energy is derived from the forward donation and 25% from backdonation. [ 5 ]
Wilkinson's catalyst is best known for catalyzing the hydrogenation of olefins with molecular hydrogen. [ 11 ] [ 12 ] The mechanism of this reaction involves the initial dissociation of one or two triphenylphosphine ligands to give 14- or 12-electron complexes, respectively, followed by oxidative addition of H 2 to the metal.
The structure of ethenium's ground state was in dispute for many years, but it was eventually agreed to be a non-classical structure, with the two carbon atoms and one of the hydrogen atoms forming a three-center two-electron bond. Calculations have shown that higher homologues, like the propyl and n-butyl cations also have bridged structures.