Special appearance of REE geochemistry of soluble hydrocarbon in coal
——An example of a middle rank coal from Weibei

The REE distribution between soluble hydrocarbons and minerals in a middle rank coal from Weibei, Shaanxi province, China, was studied with statistics method. It was found that there is a clear complementary relationship of REE between the soluble hydrocarbons and minerals. Among them, LREE and HREE have different distribution characters respectively, which are determined by the change of ions radii and inner electronic configuration. For this reason, the bigger atomic number of LREE, the less regularity of LREE distribution in soluble hydrocarbons and minerals. It is opposite for HREE. The complementary correlation or synchronous growth and decline with REE, are also observed among ingredients in the soluble hydrocarbons. This may have potential effect on the coal-formed hydrocarbons. This is another expression of “geochemical effect of REE in coal” observed by the author. In addition, the “tetra-component effect” of REE geochemistry in coal has been found.