Oxygen, sulfur, selenium, tellurium and polonium form the main subgroup of the sixth group of the table of D.I. Mendeleyev. They are called "chalcogens" that means "the forming ores". Sulfur is in the third period and has serial number 16. On an external electron layer it has 6 electrons - 3s (2) 3p (4).
Instruction
1. Sulfur under usual conditions is the solid yellow crystal substance insoluble in water, however well soluble in CS2 carbon sulfur and some other organic solvents. Three allotropic modifications of this substance are known: rhombic – α-sulfur, monoklinny – β-sulfur, and plastic – kauchukopodobny sulfur. Rhombic sulfur is steadiest, and in such look sulfur freely meets in the nature. It consists of cyclic molecules S8 in which atoms are connected by unary covalent communications.
2. Sulfur can be in the nature both in a free state, and in the form of connections. The major connections are gray – iron sulfide (pyrite) FeS2, copper gloss of CuS, silver gloss of Ag2S, lead gloss of PbS. Quite often sulfur is a part of sulfates: CaSO4∙2H2O plaster, glauberovy salt (mirabilite) Na2SO4∙10H2O, bitter (English) MgSO4∙7H2O salt, etc. It is possible to find sulfur as a part of oil, coal, in proteins of vegetable and animal organisms.
3. Free sulfur is melted from rocks in special devices – autoclaves. The laboratory receives this substance at incomplete combustion of hydrogen sulfide or by draining of solutions of sulphurous and hydrosulphuric acids: 2H2S+O2=2H2O+2S, H2SO3+2H2S=3S ↓+3H2O.
4. On the chemical properties it is gray – typical active nonmetal. It interacts with many simple and complex substances. In reactions it can be both oxidizer, and reducer (it depends on properties of reagent) and also to participate in processes of autoxidation self-recovery (disproportionation).
5. In interaction with hydrogen, metals, some nonmetals with smaller electronegativity (carbon, phosphorus) sulfur shows properties of oxidizer: H2+S=H2S, 2Na+S=Na2S, Mg+S=MgS, 2Al+3S=Al2S3, C+2S=CS2, 2P+3S=P2S3. As reducer it reacts with oxygen, halogens, acids-oxidizers: S+O2=SO2, S+Cl2=SCl2, S+3F2=SF6, S+2H2SO4 (konts.) = 3SO2 ↑+2H2O, S+2HNO3 (razb.) = H2SO4+2NO ↑, S+6HNO3 (konts.) = H2SO4+6NO2 ↑+2H2O.
6. In reactions of disproportionation (autoxidation self-recovery) with alkalis sulfur shows property of both oxidizer, and reducer at the same time. These reactions take place when heating: 3S+6NaOH=2Na2S+Na2SO3+3H2O.
7. Sulfur is applied to curing of rubber, pest control of agriculture (wax moth), in production of gunpowder, matches, sulfuric acid, etc. In medicine it skin diseases treat.