粗略地说,无机化合物可分为单质和化合物两类,而化合物又可分为酸类、鹼类、盐类和氧化物等几种,我们这里只打算谈谈酸、鹼和盐类,以及与酸、鹼有关的氧化物。随着人类对物质的性质和变化的复杂性逐渐深入地了解的时候,在这些类别的定义上,就不能不有所变更,酸、鹼定义的改变就是一个例子。酸、鹼定义的演变,是与人类对物质的认识密切地结合着的。这里我们不打算谈全部演变过程和所有的理论,只将其中最重要和最常用的几种, Roughly speaking, inorganic compounds can be divided into two kinds of simple substances and compounds, and compounds can be divided into several kinds of acids, alkalis, salts and oxides, we are only going to talk about acid, alkali and salts, and Acid and alkali-related oxides. As human beings become more familiar with the nature and changing complexity of matter, the definition of these categories can not be changed without any change. The change of acid and alkali definitions is an example. The evolution of the definition of acid and alkali is closely linked with human’s understanding of matter. Here we do not intend to talk about all the evolutionary process and all the theories, only the most important and most commonly used of them,