【原】有机化学学习笔记（第二篇）

杂化轨道理论

价键理论在解释原子的价键数目以及分子空间结构却遇到了挑战。化学家鲍林等人提出了杂化轨道理论。杂化轨道理论主要容有以下几点:

1. 1.           在同一个原子中，几个能量相近的不同类型的原子轨道可以进行线性组合，重新分配能量，确定空间方向。杂化后的电子云向一个方向集中；

2. 2.           杂化后的轨道更加有利于原子轨道之间的最大程度重叠，所以杂化轨道比原轨道成键能力更强；

3. 3.           杂化后的轨道之间在空间取得最大夹角分布，所以相互间的排斥能最小。

Hybrid orbital theory

 Valence bond theory has encountered challenges in explaining the numberof valence bonds of atoms and the structure of molecular space. Chemist Paulinget al. proposed the hybrid orbital theory. Hybrid orbital theory mainlycontains the following points:

1. 1.                   In the same atom,several different types of atomic orbitals with similar energies can becombined linearly, redistributing energy and determining the spatialorientation. The hybridized electron cloud is concentrated in one direction;

2. 2.           Hybridized orbitalsare more conducive to maximum overlap between atomic orbitals, so hybridorbitals have a stronger bonding ability than the original orbitals;

3. 3.           The hybridizedorbitals achieve the largest diagonal distribution in space, so the mutualrepulsion can be minimal.

杂化轨道以碳原子作为例子说明

未成键碳原子的核外电子排布：1s²2s²2p_x¹2p_y¹，碳原子和其他原子成键的时候，首先碳原子的2s轨道上的一个电子跃迁到2p轨道上，然后2s轨道与2p轨道进行杂化，共有三种杂化方式。

Hybrid orbitalsare illustrated by carbon atoms

Theextranuclear electrons of unbonded carbon atoms are arranged: 1s2 2s2 2p_x¹2p_y¹,when the carbon atom and other atoms are bonded, the carbon atom is the firstcarbon atom An electron in the 2 s orbit transitions to a2porbit, and then the2sorbit ishybridized with a 2porbital, with three hybridization methods.

1.1个s轨道与3个p轨道进行杂化，得到4个在空间成为正四面体的sp3杂化轨道；

2.1个s轨道与2个p轨道进行sp2杂化轨道，杂化得到3个在空间成为平面三角形的sp2杂化轨道，剩余1个没有杂化的p轨道垂直于sp2杂化轨道所在平面；

3.1个s轨道与1个p轨道进行杂化得到2个在空间成直线型的sp杂化轨道，剩余2个未参加杂化的p轨道分别垂直于sp杂化轨道所在直线。

1.1s-orbitals are hybridized with 3p-orbitals to obtain4s-p3hybrid orbitals that become regular tetrahedral in space;

2.1s-orbitals and2 p-orbitalsperforms-p2hybrid orbitals, and hybridization yields3 in space that becomeplanar trianglessp2hybrid orbital, the remaining1p-track without hybridizationis perpendicular to the plane where the s p2hybrid orbital is located;

3.1s-tracks are hybridized with 1p-orbital to obtain2s-p hybridized orbitals that are linear in space, and the remainder The two p-tracks that do not participate in the hybridizationare perpendicular to the line where the s-phybridized tracks are located.

杂化轨道类型挤以及特点

类型	轨道夹角	几何形状	没有参与杂化p轨道数目
Sp3	109°28′	正四面体	0
Sp2	120°	平面三角形	1
Sp	180°	直线型	2