Covalent bonding Molecular orbitals

The structure of a millerite crystal from Marbridge Mine, Malartic, Quebec, with the empirical formula Nio,98iFeo.oi6Coo.oo4S has been refined. The hexagonal axes were found to be o = 9.607(1) A and cq = 3.143(1) A. Within the lattice each Ni is coordinated by five S atoms and two Ni atoms. The observed Ni-S bond lengths are comparable to the expected value for a covalent bond. Molecular orbital theory was invoked to show that the millerite structure with five-fold coordination around Ni is more stable than the nickeline structure (a-NiS) with six-fold coordination about each Ni. Thereby it is rationalised that the low temperature phase (3-NiS occurs in nature and the high temperature phase a-NiS does not. 

Electronic interactions with the formation of bonding molecular orbitals (orbital energy) and the electrostatic attraction between the nuclei of atoms and electrons. These two contributions cause the bonding forces of covalent bonds. 

A simple interpretation of the nature of a covalent bond can be seen by considering some simple adaptations of the wave function. For example, it is ifi1 that is related to probability of finding the electrons. When we write the wave function for a bonding molecular orbital as ipb, that means that because... 

Still another model to represent the bonding that takes place in covalent compounds is the molecular orbital theory. In the molecular orbital (MO) theory of covalent bonding, atomic orbitals (AOs) on the individual atoms combine to form orbitals that encompass the... 

In the molecular orbital (MO) theory of covalent bonding, atomic orbitals form molecular orbitals that encompass the entire molecule. 

The formation of bonding molecular orbitals by an overlap of atomic orbitals applies not only to the Is orbitals of hydrogen, but also to other atomic orbitals. When the atomic orbitals overlap along the axis of the bond, a covalent bond, called a sigma (a) bond, results. This is normally referred to as end-on overlap. Some examples of the formation of a bonds from overlapping atomic orbitals are shown in the diagrams. 

The bonding molecular orbital in a non-polar covalent bond is completely symmetrical about the midpoint between the two atoms of the bond. 

Bonding molecular orbital in a non-polar covalent bond. 

A covalent bond occurs when two atoms share two or more electrons. More specifically, in the context of molecular orbital theory, a single covalent bond between two atoms occurs when two electrons (one from each of the atoms) occupies a bonding molecular orbital. Other terms... 

Filling the bonding molecular orbital led to the concept of the single covalent bond. 

The Permanent Dipole Moment. In a pure, single covalent bond between two atoms, the bonding electrons are shared equally between the atoms they belong equally to both nuclei. This equal sharing of the electron pair in the bonding molecular orbital is present in homonuclear molecules such as H2 and 02. However,... 

Cyclopentadienyl (Cp) complexes (see Cyclopentadienyl) are known for almost all the metals of the periodic chart, including technetium. The compounds with transition metals usually possess covalent jt Cp M bonding. The nature of the metal Cp bond is multiple. The <7-bond is formed from the overlap of an empty d orbital of Tc with one of the frUed jt bonding molecular orbital on Cp with good symmetry. Back-donation is usually also present from the filled d orbitals of Tc to one of the empty n molecular orbitals on Cp. These molecules are usually called sandwich compounds (see Sandwich Compound), when there are two Cp ligands bonded to the metal, or half-sandwich complexes (see Half-sandwich Complexes) when only one Cp ligand is present. 

We are ready now to make predictions about the stability of H2, H2, He2, and He2 (see Figure 10.24). The H2 molecular ion has only one electron, in the o-ij orbital. Since a covalent bond consists of two electrons in a bonding molecular orbital, has only half of one bond, or a bond order of Thus, we predict that the H2 molecule may be a stable species. The electron configuration of is written as (o-i ) ... 

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