Covalent bonding coordinate

HC1 is the acid, because it is donating an H+ and the H+ will accept an electron pair from ammonia. Ammonia is the base, accepting the H+ and furnishing an electron pair that the H+ will bond with via coordinate covalent bonding. Coordinate covalent bonds are covalent bonds in which one of the atoms furnishes both of the electrons for the bond. After the bond is formed, it is identical to a covalent bond formed by donation of one electron by both of the bonding atoms. 

Pauling offered the following definition of a chemical bond ... there is a chemical bond between two atoms or groups of atoms... (if) forces acting between them are such as to lead to the formation of an aggregate with sufficient stability to make it convenient for the chemist to consider it as an independent molecular species. Chemical bonds include ionic bonds, coordinate covalent... 

B) In this case, a lone electron pair on oxygen forms a bond to Ff. A coordinate covalent bond (also known as a dative covalent bond) is a special type of covalent bond in which the shared electrons come from one of the atoms only. After the bond has been formed, its strength is no different from that of a covalent bond. Coordinate covalent bonds are formed when a Lewis base (an electron donor) donates a pair of electrons to a Lewis acid (an electron accepter) the resultant componnd is then called an addnct (a compound formed by the addition reaction between two molecules). The process of forming a dative bond is called coordination. 

Coordinate Covalent Bond Coordinate Covalent Bond... 

The duoroborate ion has traditionally been referred to as a noncoordinating anion. It has shown Httie tendency to form a coordinate—covalent bond with transition metals as do nitrates and sulfates. A few exceptional cases have been reported (13) in which a coordinated BF was detected by infrared or visible spectroscopy. 

Amine—borane adducts have the general formula R3N BX where R = H, alkyl, etc, and X = alkyl, H, halogen, etc. These compounds, characterized by a coordinate covalent bond between boron and nitrogen, form a class of reducing agents having a broad spectmm of reduction potentials (5). 

The structure of AICI3 is similarly revealing. The crystalline solid has a layer lattice with 6-coordinate Al but at the mp 192.4° the stmcture changes to a 4-coordinate molecular dimer Al2Clg as a result there is a dramatic increase in volume (by 85%) and an even more dramatic drop in electrical conductivity almost to zero. The mp therefore represents a substantial change in the nature of the bonding. The covalently bonded... 

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. 

In principle, any molecule or anion with an unshared pair of electrons can act as a Lewis base. In other words, it can donate a lone pair to a metal cation to form a coordinate covalent bond. In practice, a ligand usually contains an atom of one of die more electronegative elements (C, N, O, S, F, Cl, Br, I). Several hundred different ligands are known. Those most commonly encountered in general chemistry are NH3 and HzO molecules and CN , Cl-, and OH- ions. 

The boron atom in BF5 can complete its octet if an additional atom or ion with a lone pair of electrons forms a bond by providing both electrons. A bond in which both electrons come from one of the atoms is called a coordinate covalent bond. For example, the tetrafluoroborate anion, BF4 (31), forms when boron trifluoride is passed over a meral fluoride. In this anion, the formation of a coordinate covalent bond with a fluoride ion gives the B atom an octet. Another example of a coordinate covalent bond is that formed when boron trifluoride reacts with ammonia ... 

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. 

Boron trichloride, a colorless, reactive gas of BC13 molecules, behaves chemically like BF3. However, the trichloride of aluminum, which is in the same group as boron, forms dimers, linked pairs of molecules. Aluminum chloride is a volatile white solid that vaporizes at 180°C to a gas of Al2Cl6 molecules. These molecules survive in the gas up to about 200°C and only then fall apart into A1C13 molecules. The Al,CI6 molecule exists because a Cl atom in one AlCI, molecule uses one of its lone pairs to form a coordinate covalent bond to the Al atom in a neighboring AICI molecule (33). This arrangement can occur in aluminum chloride hut not boron trichloride because the atomic radius of Al is bigger than that of B. 

A coordinate covalent bond is a bond in which both bonding electrons come from the same atom (Section 2.11). 

When a Lewis base donates an electron pair to a Lewis acid, the two species share the pair and become joined by a coordinate covalent bond, a bond in which both electrons come from one of the atoms (see Section 2.11). 

A proton (H+) is an electron pair acceptor. It is therefore a Lewis acid because it can attach to ( accept") a lone pair of electrons on a Lewis base. In other words, a Bronsted acid is a supplier of one particular Lewis acid, a proton. The Lewis theory is more general than the Bronsted-Lowry theory. For instance, metal atoms and ions can act as Lewis acids, as in the formation of Ni(CO)4 from nickel atoms (the Lewis acid) and carbon monoxide (the Lewis base), but they are not Bronsted acids. Likewise, a Bronsted base is a special kind of Lewis base, one that can use a lone pair of electrons to form a coordinate covalent bond to a proton. For instance, an oxide ion is a Lewis base. It forms a coordinate covalent bond to a proton, a Lewis acid, by supplying both the electrons for the bond ... 

To remove an ion, we can use the fact that many metal cations are Lewis acids (Section 10.2). When a Lewis acid and a Lewis base react, they form a coordinate covalent bond and the product is called a coordination complex. In this section, we consider complexes in which the Lewis acid is a metal cation, such as Ag+. An example is the formation of Ag(NI 1,)2+ when an aqueous solution of the Lewis base ammonia is added to a solution of silver ions ... 

The hydrated ion [Cu(H20)6]2+ is an example of a complex, a species consisting of a central metal atom or ion to which a number of molecules or ions are attached by coordinate covalent bonds. A coordination compound is an electrically neutral compound in which at least one of the ions present is a complex. However, the terms coordination compound (the overall neutral compound) and complex (one or more of the ions or neutral species present in the compound) are often used interchangeably. Coordination compounds include complexes in which the central metal atom is electrically neutral, such as Ni(CO)4, and ionic compounds, such as K4[Fe(CN)6]. 

The formation of coordinate covalent bonds is described in Sections 2.11 and 10.2. 

A coordinate covalent bond, represented by an arrow, is one in which both electrons come from the same atom that is, the bond can be regarded as being formed by the overlap of an orbital containing two electrons with an empty one. Thus trimethylamine oxide would be represented... 

In the polyatomic ion the formation of a coordinate covalent bond between nitrogen and hydrogen involves —... 

Bond type Covalent Ionic, hydrophobic, hydrogen bond, metal-ligand coordination... 

The basis for the toxicological activity of this substance is the reaction of cobalt ion with cyanide ion to form a relatively nontoxic and stable ion complex. The hexacyanocobaltate ion contains a Co2+ central metal ion with six cyanide ions as ligands. This coordination complex involves six coordinate covalent bonds whereby each cyanide ion supplies a pair of electrons to form each covalent bond with the central cobalt ion. The formation constant for the hexacyanocobaltate ion is even larger than for dicobalt EDTA,3 and thus the cobalt ion preferentially exchanges an EDTA ligand for six cyano ligands ... 

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... 

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