稀土是指元素周期表上原子序数57～71的15个镧系元素以及化学性质相似的钪和钆共17个元素的总称。稀土这个名称是历史上沿用下来的旧名。其实它既不稀(在地壳中比铜、铅、锌还多)也不土(它们是典型的金属元素)。由于它们的化学性质很相似,而且常和铀、钍等元素伴在一起,很难把它们彼此分开,所以在农业上施用的硝酸稀土是它们的混合物。稀土元素具有许多优良的物 Rare earth refers to the periodic table on the atomic number 57 ~ 71 15 lanthanides and chemically similar scandium and gadolinium total of 17 elements in general. The name of rare earth is the old name down in history. In fact, it is neither dilute (more than copper, lead, or zinc in the crust) nor earth (they are typical metallic elements). Because of their very similar chemical properties and their frequent association with elements such as uranium and thorium, it is difficult to separate them from one another, so agriculturally applied rare earth nitrate is a mixture of these. Rare earth elements have many good things