From Natural Gifts to Industrial Backbone
In Earth's evolutionary history,sulfur, nitrogen, siliconthey are not only the fundamental building blocks of Earth's crust and life, but also the cornerstone of modern chemical civilization. Silicon forms rocks and soil as silica and silicates, and today powers the microelectronics industry of the information age in its high-purity elemental form. Sulfur and nitrogen complete their natural cycles amid thunderstorms and volcanic eruptions; once captured by humans, they are transformed into sulfuric acid and ammonia, nourishing agriculture and national defense.
Core Properties and Valence Logic
- Sulfur Element (S): located in Group VIA of the third period. Common oxidation states are -2, 0, +4, +6. Elemental sulfur is commonly known as sulfur, a yellow crystalline solid that is brittle, poorly soluble in water, slightly soluble in alcohol, and readily soluble in $CS_2$.
- Atomic Structure Determines Properties: The sulfur atom has six electrons in its outermost shell, making it prone to gaining electrons and exhibiting oxidizing behavior (forming -2 oxidation state), while also showing reducing properties when reacting with strong oxidizing agents (forming +4 or +6 oxidation states).
- Silicon (Si): located near the boundary between metals and nonmetals in the periodic table, which determines its unique electrical properties as a semiconductor material.
Industrial Tip: Sulfur Washing
In the lab, if sulfur adheres to the inside of a test tube, use $CS_2$ for cleaning. Due to the 'like dissolves like' principle, elemental sulfur dissolves extensively in the nonpolar solvent $CS_2$. For heated cleaning, hot $NaOH$ solution can also be used (which triggers a disproportionation reaction).