33. CARBON, SILICON AND IV-A ELEMENTS OF SUBGROUP.

In carbon podruppa входыт elements: carbon, silicon, germanium, tin, lead

STAY IN THE NATURE

Content in crust: carbon - 0,087%, silicon - 25,8%, germanium - 0,00056%, tin - 0,0035%, lead - 0,0018%

Physical properties of elements of subgroup of carbon.

Element	Carbon With	Silicon Si	Germanium Ge	Tin Sn	Lead Pb
Property
Order number of element	6	14	32	50	82
Relative atomic mass	12,011	28,086	72,61	118,711	207,2
Temperature of melting, C0	3850	1423	959	232	327
G/cm3 density	3,51 2,22	2,33	5,35	7,28	11,34
Oxidation levels	+4, +2,-4	+4, +2,-4	+4, +2	+4, +2	+1, +3

 

ALLOTROPIC MODIFICATIONS OF CARBON.

diamond graphite carbene fullerit sp3-hybridization, tetrahedral - bonds strong, covalent, therefore very firm sp2-hybridization, bedded structure, long distance and fragile interlaminar banding, therefore soft sp-hybridization linear polymer, solid matter consists of C60, C70 fullerenes, shaped spheres. Let's dissolve in organic solvents. Receive at evaporation of graphite in the atmosphere of helium.

Receiving carbon and silicon

carbon	silicon
Receive heating without access of air from wood and каменног coal, and also when cracking methane: CH4=C+2H2	SiO2+C=Si+2CO SiH4=Si+2H2 2Mg+SiO2=2MgO+Si

Chemical properties of carbon and silicon.

carbon	silicon
reducer 1.s+o2=co2-lower than 500 0C 2. With +H2O=CO+H2 - it is higher than 1200 0C When heating 4.4HNO3+3C=3CO2+4NO+2H2O oxidizer Ca+2C=CaC2 calcium carbide 2H2+C=CH4	reducer 1.Si+2F2=SiF4 2.Si+O2=SiO2 3.Si+Cl2=SiCl4 4.Si+2NaOH+H2O=Na2SiO3+2H2-heating. 5.Si+C=SiC 6.2N2+3Si=Si3N4 (> 1000 0C) oxidizer 2Ca+Si=Ca2Si calcium silicide

Carbon compound and silicon.

carbon	silicon
1. Hydrocarbons (CH4, C2H2, C6H6, etc.) 2. Carbides a) metal character Fe3C b) ionic carbides Al4C3, CaC2, etc. 3) carbon oxides (II) and (III) 4) salts of coal acid carbonates	1. Silicon oxide 2. Salts of silicon acid-silicates 3. Cements: usual (CaO, SiO2) CaO · SiO2+CO2+H2O=CaCO3+H2SiO3 portland cement (mix Ca3SiO5, Ca2SiO4, Ca3(AlO3) 2) Ca3SiO5+H2O=Ca2SiO4+Ca(OH)2 Ca2SiO4+4H2O=Ca2SiO4 · 4H2O Ca3(AlO3)2+6H2O=Ca3(AlO3)2 4. Glass

 

   

 

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