rare base是什么意思

用法例句

From the structure date of the rare earth ethylsulphates RE(C2H5SO4)3·9H2O(RE=La→Lu,except Pm),their efficient valence electrons,efficient valence densities andaverage coordinatiOn numbers of bonds etc,have been calculated by using the chemical bondtheory of complex crystals of dielectric description.

利用复杂晶体化学键的介电描述理论，计算了稀土乙基硫酸盐晶体Ｒｅ（Ｃ＿２Ｈ＿５ＳＯ＿４）＿３·９Ｈ２Ｏ，（Ｒｅ＝Ｌａ→Ｌｕ，不含Ｐｍ）各化学键的键参数，讨论了每一个键的键性质，结果显示，晶体中存在１６种类型和性质不同的化学键。