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Typical Lewis bases are conventional amines such as ammonia and alkyl amines. Other common Lewis bases include pyridine and its derivatives. Some of the main classes of Lewis bases are amines of the formula NH 3−x R x where R = alkyl or aryl. Related to these are pyridine and its derivatives. phosphines of the formula PR 3−x Ar x.
Ammonia forms 1:1 adducts with a variety of Lewis acids such as I 2, phenol, and Al(CH 3) 3. Ammonia is a hard base (HSAB theory) and its E & C parameters are E B = 2.31 and C B = 2.04. Its relative donor strength toward a series of acids, versus other Lewis bases, can be illustrated by C-B plots.
[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.
Adducts between them have the formula X 3 A←DY 3 with a dative covalent bond, shown symbolically as ←, between the atoms A (acceptor) and D (donor). Compounds of group 16 with a formula DX 2 may also act as Lewis bases; in this way, a compound like an ether, R 2 O, or a thioether, R 2 S, can act as a Lewis base. The Lewis definition is not ...
Ammonium is a modified form of ammonia that has an extra hydrogen atom. It is a positively charged molecular ion with the chemical formula NH + 4 or [NH 4] +.It is formed by the addition of a proton (a hydrogen nucleus) to ammonia (NH 3).
Carbon monoxide exemplifies a Lewis structure with formal charges: To obtain the oxidation states, the formal charges are summed with the bond-order value taken positively at the carbon and negatively at the oxygen. Applied to molecular ions, this algorithm considers the actual location of the formal (ionic) charge, as drawn in the Lewis structure.
[2] [3] [4] Various computational criteria for the presence of lone pairs have been proposed. While electron density ρ(r) itself generally does not provide useful guidance in this regard, the Laplacian of the electron density is revealing, and one criterion for the location of the lone pair is where L(r) = –∇ 2 ρ(r) is a local
2.05×10 −2 g/cm 3 65 °C: 2947 kPa 0.53596 g/cm 3 70 °C: 3312 kPa 0.52632 g/cm 3: 2.65×10 −2 g/cm 3 75 °C: 3711 kPa 0.51626 g/cm 3 80 °C: 4144 kPa 0.50571 g/cm 3: 3.41×10 −2 g/cm 3 85 °C: 4614 kPa 0.49463 g/cm 3 90 °C: 5123 kPa 0.48290 g/cm 3: 4.39×10 −2 g/cm 3 95 °C: 5672 kPa 0.47041 g/cm 3: 100 °C: 6264 kPa 0.45693 g/cm 3: ...