The electrons are not equally shared and the carbon hogs the electrons a little bit more than the hydrogen, so the carbon is electron-rich and the hydrogen is just a little bit electron-deficient.

电子不是平均共享的,碳原子比氢原子吸引电子,更强烈一点点，所以碳原子是富电子,而氢原子是缺电子。

固态化学导论课程节选 : 麻省理工公开课