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The arenes have the formula C n H n, substituted derivatives (for example C n (CH 3) n) and heterocyclic derivatives (for example BC n H n+1). Because the metal is usually situated between the two rings, it is said to be "sandwiched". A special class of sandwich complexes are the metallocenes.
Protonation of metal hydroxides gives aquo complexes: L n M−OH + H + ⇌ L n M−OH + 2 where L n is the ligand complement on the metal M. Thus, aquo ligand is a weak acid, of comparable strength to acetic acid (pK a of about 4.8). [6] In principle but not very commonly, metal hydroxides undergo deprotonation, yielding oxo complexes:
The metallic radius is defined as one-half of the distance between the two adjacent metal ions in the metallic structure. This radius depends on the nature of the atom as well as its environment—specifically, on the coordination number (CN), which in turn depends on the temperature and applied pressure.
A solid with extensive hydrogen bonding will be considered a molecular solid, yet strong hydrogen bonds can have a significant degree of covalent character. As noted above, covalent and ionic bonds form a continuum between shared and transferred electrons; covalent and weak bonds form a continuum between shared and unshared electrons.
Bifurcated H-bond systems are common in alpha-helical transmembrane proteins between the backbone amide C=O of residue i as the H-bond acceptor and two H-bond donors from residue i + 4: the backbone amide N−H and a side-chain hydroxyl or thiol H +. The energy preference of the bifurcated H-bond hydroxyl or thiol system is -3.4 kcal/mol or -2. ...
A steel bottle containing MgCp 2 (magnesium bis-cyclopentadienyl), which, like several other organometallic compounds, is pyrophoric in air.. Organometallic compounds are distinguished by the prefix "organo-" (e.g., organopalladium compounds), and include all compounds which contain a bond between a metal atom and a carbon atom of an organyl group. [2]
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There are two possible structures for hydrogen cyanide, HCN and CNH, differing only as to the position of the hydrogen atom. The structure with hydrogen attached to nitrogen, CNH, leads to formal charges of -1 on carbon and +1 on nitrogen, which would be partially compensated for by the electronegativity of nitrogen and Pauling calculated the net charges on H, N and C as -0.79, +0.75 and +0.04 ...