Sulfur is a nonmetallic element with the chemical symbol S and an atomic number of 16. Pure sulfur is yellow crystal, also known as sulfur or yellow sulfur. Elemental sulfur is insoluble in water, slightly soluble in ethanol, and easily soluble in carbon disulfideCS2.
1.Physical properties
- Sulfur is typically a pale yellow crystal, odorless and tasteless.
- Sulfur has many allotropes, all of which are composed of S8 cyclic molecules. The most common ones are orthorhomb sulfur (also known as rhombic sulfur, α-sulfur) and monoclinic sulfur (also known as β-sulfur).
- Orthorhombic sulfur is a stable form of sulfur, and when heated to around 100 °C, it can be cooled to obtain monoclinic sulfur. The transformation temperature between orthorhombic sulfur and monoclinic sulfur is 95.6 °C.orhombic sulfur is the only stable form of sulfur at room temperature. Its pure form is yellow-green (the sulfur sold on the market appears more yellow due the presence of trace amounts of cycloheptasulfur). Orthorhombic sulfur is actually insoluble in water, has poor thermal conductivity, is a good electrical insulator.
- Monoclinic sulfur is the countless needle-like crystals left over after melting sulfur and pouring off the excess liquid. Monoclinic sulfur orthorhombic sulfur are variants of elemental sulfur at different temperatures. Monoclinic sulfur is only stable above 95.6 ℃, and at temperature, it slowly transforms into orthorhombic sulfur. The melting point of orthorhombic sulfur is 112.8℃, the melting point of monoclinic sulfur is 119℃. Both are highly soluble in CS2.
- There is also elastic sulfur. Elastic sulfur is a dark yellow, elastic solid that is less soluble in carbon disulfide than other allotropes sulfur. It is insoluble in water and slightly soluble in alcohol. If molten sulfur is quickly poured into cold water, the long-chain sulfur is fixed, stretchable elastic sulfur. However, it will harden over time and become monoclinic sulfur.
2.Chemical properties
- Sulfur can burn in the air, reacting with oxygen to form sulfur dioxide (SO₂) gas.
- Sulfur reacts with all the halogens upon heating. It burns in fluorine to form sulfur hexafluoride. Liquid sulfur with chlorine to form the strongly irritating disulfur dichloride (S2Cl2). An equilibrium mixture containing the red sulfur dichloride (SCl) can be formed when chlorine is in excess and a catalyst, such as FeCl3 or SnI4, is used.
- Sulfur can react with hot potassium hydroxide (KOH) solution to form potassium sulfide and potassium thiosulfate.
- Sulfur does not react with water and non-oxidizing acids. Sulfur reacts with hot nitric acid and concentrated sulfuric acid and can be oxidized into sulfuric acid and sulfur dioxide.
3.Application field
- Industrial use
The main uses of sulfur are in the production of sulfur compounds such as sulfuric acid, sulfites, thiosulfates,ocyanates, sulfur dioxide, carbon disulfide, disulfur dichloride, trichlorosulfonated phosphorus, phosphorus sulf, and metal sulfides. More than 80% of the world's annual sulfur consumption is used in the production of sulfuric acid. Sulfur also extensively used in the production of vulcanized rubber. When raw rubber is vulcanized into vulcanized rubber, it acquires high elasticity, heat resistance tensile strength, and insolubility in organic solvents. Most rubber products are made of vulcanized rubber, which is produced by reacting raw rubber with and accelerators at certain temperatures and pressures. Sulfur is also needed in the production of black powder and matches, and it is one of the main raw for fireworks. Additionally, sulfur can be used in the production of sulfurized dyes and pigments. For example, calcining a mixture of kaolin, carbon, sulfur, diatomaceous earth, or quartz powder can produce a blue pigment called ultramarine. The bleach industry and pharmaceutical industry also consume a portion sulfur.
- Medical use
Sulfur is one of the ingredients in many skin disease medications. For example, tung oil is heated with sulfur to sulfonate with sulfur acid and then neutralized with ammonia water to obtain sulfonated tung oil. A 10% ointment made from it has anti-inflammatory and deelling effects and can be used to treat various skin inflammations and swellings.
Post time: Dec-09-2024