How to tell the type of orbital hybridization of a molecule or ion

The number of electrons in the valence shell of the central atom + the number of electrons provided by the accessory atom - valence state) 2 The number obtained is the number of hybrid orbitals, and then the hybridization method is selected according to this number.

The calculation steps are as follows:

1. Determine the number of lone electron pairs of the central atom.

2. Find the number of atoms connected to the central atom (i.e., the number of bonds formed) 3. If the sum of the two is equal to 2, then the central atom adopts sp hybridization; If it is equal to 3, then the central atom is hybridized with sp2, and if it is equal to 4, then the central atom is hybridized with sp3.

As in ethylene, the carbon atom is the central atom and the number of atoms attached to it is 3, while the carbon has 4 valence electrons.

Uniform bonds (3 bonds plus 1 bond, so the number of lone pairs of electron pairs.

is zero shouting, so 0+3=3, take sp2 hybridization;

Such as hydrogen oxide. The oxygen atom is the central atom, the number of atoms connected to the oxygen atom is 2, and the oxygen has two lone pairs of electrons left, so 2+2=4, and sp3 hybridization is adopted.

According to the theory of valence shell electron pair repulsion, the number of valence electron pairs, the number of bonds, and the number of lone electron pairs of the central atom are known, and if the number of bonds and lone electron pairs is known, the number of valence electron pairs of the central atom can be reversed, so as to judge the hybridization mode.

The substitution reaction in organic chemistry is a reaction in which some atoms or groups of atoms in an organic molecule are replaced by other atoms or clusters, and according to the substitution reaction mechanism, the structure and bonding mode of the central atom should remain unchanged after substitution. This enlightens that for some complex molecules, some of the atomic clusters can be replaced by atoms to become simple and familiar molecules, and the spatial configuration and hybrid orbital type of the original molecule can be judged according to the spatial configuration and hybrid orbital type of the molecule.

1. Determine the number of lone electron pairs of the central atom.

2 Find out the number of atoms (i.e. the number of bonds formed) attached to the central atom.

3 If the sum of the two equals 2, then the central atom is sp hybridized; If it is equal to 3, then the central atom is hybridized with sp2; If it is equal to 4, then the central atom is hybridized with sp3.

For example, ethylene, the carbon atom is the central atom, and the number of atoms connected to it is 3, and the 4 valence electrons of carbon are homogeneous bonds (3 bonds plus 1 bond), so the number of lone pair electron pairs is zero, so 0+3=3, sp2 hybridization is adopted.

For example, hydrogen oxide, the oxygen atom is the central atom, the number of atoms connected to the oxygen atom is 2, and the oxygen has two pairs of lone pairs of electrons, so 2+2=4, sp3 hybridization is adopted.

The main types of hybridization are sp, sp2, sp3A simple way to do this is to see how many single electrons and lone pairs there are in the excited atom. For example, the c atom has 4 electrons after excitation, which is sp3.

If there are 3, it is SP2, and if there is one, it is SP. The actual molecular configuration must take into account lone pairs, such as ammonia.

The principle of valence shell electron pair repulsion: divide the sum of the number of valence shell electrons of each atom in the compound by two, and the number obtained is the number of valence shell electron pairs. Where the number of valence shell electrons of the oxygen group element is calculated as 0 when the oxygen group element is not acting as the central atom.

The number of electron pairs of the valence shell obtained is the corresponding hybridization method. (2 is sp hybridization, 3 is sp2, 4 is sp3 hybridization.)For example, methane is CH4, so the valence shell electron pair is (4+4=8,8 2=4,) so it is sp3 hybridized; Another example is SO2, the sulfur of the central atom should be counted, and the oxygen of the non-central atom should not be counted, so it is 6 2 = 3, so it is sp2 hybridization. Wait.

1. Find the central atom.

2. Calculate the number of electron pairs provided.

3. Determine hybridization.

Example: SO2: central atom S, donating 6 electrons (consistent with the main group ordinal number), O not providing (when the oxygen group element is a surrounding atom, it does not provide electrons; If it is the central atom, it is the same as the ordinal number of the main group, i.e., 6).

There are 3 pairs of electrons in total, 3 orbitals, so sp2 hybridization.

BCl3: B donates 3 electrons and Cl donates 1 electron (peripheral atoms don't provide electron number = 8 - main group ordinal number), so there are a total of 3 pairs of electrons and 3 orbitals, so sp2 hybridization.

Got it? If you still don't understand, please refer to the "Inorganic Chemistry" Jilin University, Wuhan University and other three universities co-edited the third edition of the first volume of the molecular structure part, which is very detailed.

The method provided by Renjiao Elective 3 is not good.

First, from the perspective of early rock structure.

1.The tetrahedral configuration is sp3 hybridized.

2.The planar type is sp2 hybridized.

3.The linear type is SP hybridized.

Second, the nuclear tomb from the way of bonding.

1.The carbon-carbon single bond is sp3 hybridized.

2.The carbon-carbon double bond is sp2 hybridized.

3.The carbon-carbon triple bond is sp hybridized.

First, from the perspective of early rock structure.

1.The tetrahedral configuration is sp3 hybridized.

2.The planar type is sp2 hybridized.

3.The linear type is SP hybridized.

Second, the nuclear tomb from the way of bonding.

1.The carbon-carbon single bond is sp3 hybridized.

2.The carbon-carbon double bond is sp2 hybridized.

3.The carbon-carbon triple bond is sp hybridized.