A pure, macroscopically homogeneous substance consisting of atoms or ions of two or more different elements in definite proportions that cannot be separated by physical means. A compound usually has properties unlike those of its constituent elements.

• 化合物一种纯净的宏观上性质相同的物质，它由两种或多种不同元素的原子或离子按一定的比例化合而成，并且不能用物理方法将其分离。化合物一般具有与其合成元素不同的性质