And what it's used is to convert one type of group, what's called a carboxylic acid into another type of very reactive intermediate, which is called an acid chloride.

它被用来将一类被称作羧酸的化合物，转化成另外一类活性很高的反应中间体,也就是酰氯。

麻省理工公开课 - 化学原理课程节选

- So, for example, if he was talking about the group one metals, he noticed these were all very soft reactive metals, those were grouped together.

比如，他在讨论，I，族金属，注意到它们都是质地较软的活性金属，这些被归到一类。

麻省理工公开课 - 化学原理课程节选