Coordinate covalent bonds nitrogen atom

The nitrogen atom of each NH3 molecule contributes a pair of unshared electrons to form a covalent bond with the Cu2+ ion. This bond and others like it, where both electrons are contributed by the same atom, are referred to as coordinate covalent bonds. 

The Lewis structure of the product, a white molecular solid, is shown in (32). In this reaction, the lone pair on the nitrogen atom of ammonia, H3N , can be regarded as completing boron s octet in BF3 by forming a coordinate covalent bond. 

The sodium and calcium salts of EDTA (ethylenediaminetetraacetic acid, Fig. 9.3.1.) are common sequestrants in food products. A three-dimensional representation of EDTA is shown in color Fig. 9.3.2. The EDTA ion is an especially effective sequestrant, forming up to six coordinate covalent bonds with a metal ion. These bonds are so named because a lone pair of electrons on a single atom serves as the source of the shared electrons in the bond between the metal ion and EDTA. The two nitrogen atoms in the amino groups and the oxygen... 

FIGURE 5.16 The electron dot structure of a nitrogen atom (left) and an ammonia molecule (right). The pair of electrons above the nitrogen is the nonbonding pair available for coordinate covalent bonding. 

One final point about covalent bonds involves the origin of the bonding electron pair. Although most covalent bonds form when two atoms each contribute one electron, bonds can also form when one atom donates both electrons (a lone pair) to another atom that has a vacant valence orbital. The ammonium ion (NH4+), for example, forms when the two lone-pair electrons from the nitrogen atom of ammonia, NH3, bond to H +. Such bonds are called coordinate covalent bonds. 

A coordinate covalent bond—the nitrogen atom donates both electrons... 

A chemical bond can be defined as an interaction between two or more atoms that holds them together by reducing the potential energy of their electrons. In most bonds between two atoms, electrons are either shared or transferred Another type of bond between two atoms is a coordinate covalent bond. In this bond, the bonding pair of electrons originates on one of the bonded atoms. H3 N-BF3 is a molecule that has a coordinate covalent bond. The dash in the formula indicates the bond position where both electrons are contributed by the nitrogen atom. 

This reaction (between Cd2+ and NH3) involves the formation of a coordinated covalent bond where the element nitrogen of NH3 shares its single unshared electron pair with Cd2+ (see Chapter 1). The number of water molecules that could be displaced from the cation s hydration sphere depends on the concentration of NH3 and the strength by which it associates with the metal ion. In these complex ions, otherwise known as metal-ammine complexes, the metal is called the central atom and the associated molecule or ion is called the ligand. 

In this example the free pair of electrons that is located on the nitrogen atom donates two electrons toward the bond that is formed with the hydrogen ion. Normally when a covalent bond is formed, one electron comes from each of the atoms that are bonding. In this case, the hydrogen ion did not donate any electrons toward this bond. When one atom donates both electrons in the covalent bond the bond is called a coordinate covalent bond. 

Nitrogen has three half-occupied p orbitals available for bonding, all perpendicular to one another. Since the nitrate ion is known to be planar, we are forced to assume that the nitrogen outer electrons are sp2 hybridized. The addition of an extra electron fills all three hybrid orbitals completely. Each of these filled sp2 orbitals forms a a bond by overlap with an empty oxygen 2pz orbital this, you will recall, is an example of coordinate covalent bonding, in which one of the atoms contributes both of the bonding electrons. 

In this reaction between boron trihydride (BH3) and ammonia (NH3), the nitrogen atom donates both electrons that are shared by boron and ammonia, forming a coordinate covalent bond. 

The ion has a vacant orbital, which accepts a share in the lone pair on nitrogen. The formation of a covalent bond by the sharing of an electron pair that is provided by one atom is called coordinate covalent bond formation. This type of bond formation is discussed again in Chapters 10 and 25. 

The shape of cation (CH3)4N" is tetrahedral. The nitrogen atom is at the centre of the cation. Nitrogen has five valence electrons. Three electrons form bonds to CH3, plus one lone pair forms coordinate covalent bond with... 

The nitrogen atom shares both electrons to form the coordinate covalent bond. 

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