苏联共产党第二十次代表大会关于第六个五年计划的指令中指出,要大大地提高希有金属的产量,保证电子工业、无线电工程和耐高温合金之生产的进一步发展。关于希有金属的知识以及希有金属在国民经济上的用途到现在为止那些是已经知道的呢? 现在已知有101种化学元素,其中50种以上一般是看作希有金属的,这些希有金属分别位于门捷列夫周期系的不同族中,具有不同的理-化性质。门捷列夫在发现周期律的当时, In the directive of the Twentieth Congress of the Communist Party of the Soviet Union on the Sixth Five-Year Plan, it was pointed out that it is necessary to greatly increase the production of metal and ensure the further development of the production of the electronics industry, radio engineering and high temperature resistant alloys. There are already 101 chemical elements known so far, of which more than 50 are generally considered to be Metals, these Metals are located at Mendeleev cycle of different families, with different physico-chemical properties. Mendeleev at the time of discovering the periodic law,