The inventor of the Periodic Table of Elements, Dmitri Ivanovich also penned the extremely well received textbook entitled "Principles of Chemistry" which is used to this day in classrooms all over the world. Some of the areas that he was considered an expert in include meteorology, geology, physics, and the technology behind chemistry. These principles were derived from his extensive laboratory research, which was performed throughout his lifetime. He was also one of the founders of the Russian Chemical Society. These findings were then applied to the agriculture field and to helping refine industrial interests.
One concept that fascinated Dmitri Ivanovich Mendeleev throughout his research undertakings was the idea of the ether. He crafted a hypothesis that there were elements that are lighter than hydrogen, which was the element that had already been discovered. One of these was hypothesized to be a gas that was capable of penetrating every other bit of matter on the planet, and the other was deemed to be slightly heavier than this yet also just as pervasive. The heavier one was named coronium, and Mendeleev spent a great deal of his time working on the theoretical compounds and discovery of these two elemental agents.
Other physical elements of science that Dmitri Ivanovich Mendeleev was heavily involved with included how liquids expand with heat, and the molecular reasons behind this. He worked out a law that helped describe how gasses expand, and also defined the absolute boiling point of such substances as liquid by investigating the heat and exact point of vaporization. These laws were well ahead of their time, and were later fleshed out by other scientists over a century later. He was also ahead of his time in terms of the way that he was able to anticipate the weights and properties of various elements that had not yet been discovered or isolated in nature, which he put into his Periodic Table of Elements. His genius was in pulling out these theories that could later be proven when technology improved.
These discoveries were all extremely important at the time, and Dmitri Ivanovich Mendeleev was considered to be one of the world's foremost scientists, for which he received no small amount of awards and professional recognitions. In addition to penning the Periodic Table of Elements, he also brought the metric system to Russia, and invented a smokeless powder when commissioned by the Russian Navy to do so. The breadth of range of subject matter that Mendeleev was interested in surpassed his contemporaries.