n.同数性，（同分）异构现象，同质异能现象

The two molecules are structural isomers, meaning they have the same molecular formula but different structures.
这两个分子是结构异构体，意味着它们具有相同的分子式但结构不同。
In organic chemistry, there are three main types of isomerism: structural, stereoisomerism, and geometric isomerism.
在有机化学中，异构体主要有三种类型：结构异构、立体异构和几何异构。
Stereoisomers are a type of isomer that differ in their spatial arrangement of atoms, yet have the same chemical properties.
立体异构体是一种异构体，它们在原子的空间排列上有所不同，但却具有相同的化学性质。
The compound exhibits optical isomerism, which means it exists as a pair of molecules that are mirror images of each other.
该化合物表现出光学异构性，这意味着它存在一对作为彼此镜像的分子。
Isomerism can lead to significant differences in biological activity, such as in drugs where one isomer may be highly effective while another is ineffective or even toxic.
异构体可能导致生物活性的显著差异，例如在药物中，一种异构体可能非常有效，而另一种则无效甚至有毒。
Geometric isomerism occurs when the shape of the molecule changes due to the restricted rotation around certain bonds.
几何异构体发生在由于某些键的旋转受限导致分子形状改变时。
Structural isomers are compounds with the same molecular formula but different connectivity of atoms, leading to different physical and chemical properties.
结构异构体是具有相同分子式的化合物，但原子连接方式不同，导致不同的物理和化学性质。
Stereoisomers can often be distinguished by their optical activity, which can be measured using polarimetry.
立体异构体通常可以通过其光学活性来区分，这可以通过偏光计测量得到。
In some cases, the existence of isomers can complicate the synthesis of a desired compound, necessitating careful control over reaction conditions.
在某些情况下，异构体的存在可能会使合成所需化合物变得复杂，需要仔细控制反应条件。
Isomerism is not limited to organic compounds; it also applies to inorganic and biochemical systems.
异构体不仅限于有机化合物，也适用于无机和生物化学系统。