At 5 a.m. on January 20, 1907, Mendeleev suffered a myocardial infarction and fell asleep in a chair. At that time, he still held a pen in his hand and an unfinished book in front of him. At the memorial service, his students made an elegiac couplet using symbols of 18 elements such as "Ga, Sc, Ge, Os, Ir, Sn..." to symbolize Mendeleev's great achievements in his life. To this day, Mendeleev's famous saying still rings in people's ears from time to time: "What is a genius? If you work hard all your life, you will become a genius!"