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Showing posts with label 14th Group: CARBON FAMILY:. Show all posts
Showing posts with label 14th Group: CARBON FAMILY:. Show all posts

Sunday, April 24, 2022

14th Group: Carbon Family:

(A) Silicon compounds:

Illustrative Examples:

(B) Carbon Allotropes and compounds:


Illustrative Examples:




(7) Buckminsterfullerene: Bucky Balls: Allotrope of Carbon:

Tuesday, December 22, 2020

Why are the properties of CO2 and SiO2 different?

Their properties are very different because CO2 is a chain-like three-atom  molecule and SiO2 is a solid compound with the three dimensional bridges between silicon and oxygen atoms.

Wednesday, October 7, 2020

What is "Zeolite's" ?

 Zeolite ia Sodium, Potassium salt of alumino silicate. The general formula of Zeolite is as  

                                M x/n [(AlO2)x (SiO2)] · mH2O.

                     Where M= Na+, K+, NH4+, Li+, Ca+2, Mg+2

                            Examples: Na2[(AlO2)12 (SiO2)]·27H2O

Zeolite’s have truncated Octahedral structure.

Zeolite’s are molecular sieves (Chalni) , are used to removed hardness of water and sulphate unit from detergents.

Related Questions:

Is all the C-C bond length in fullerene is equal ?

 

 
 
 
 
 
 
 
 
 
 
 
 

Monday, October 5, 2020

Why does SiCl4 undergo hydrolysis whereas CCl4 doesn't?

Their is mainly two reason that's why  SiCl4 undergo hydrolysis while CCl4 Not .
First is steric hindrance , in case CCl4 Cl atoms  blocking the C atom and preventing water molecules (nucleophile) from attacking it easily. While in case SiCl4 , Si is larger than C so  there is less crowding so it is more susceptible to attack by the (water molecules) nucleophile.
Second reason is presence of vacant d orbital. Thus, Water, acting as nucleophile can attack easily at the vacant d orbital of Si and reaction will occur through penta co-ordinated transition state.But  in case of CCl4 due to the absence of d orbital and smaller size of carbon makes ligand environment more crowded and nucleophile can't easily attack to the central atom.
 

Thursday, October 1, 2020

Graphite is considere, thermodynamically the most stable allotrope of carbon why ?

Thermodynamically the most stable allotrope of carbon is considered to be graphite. This is due standard enthalpy of formation of graphite is taken zero .while enthalpy of formation of diamond and fullerenes are 1.90 KJ/Mole and 38.1 KJ/Mole respectively.

Reference: 

STRUCTURE OF GRAPHITE:

Related-topics: 

STRUCTURE OF FULLERENCES :

STRUCTURE OF DIAMOND :

What are structural information of Dimomd ?

All the carbon atom of fullerenes (C60) are equivalent but all C-C bond are not equivalent why ?

Related Questions:

What are Silicates ? explain different type of silicates with examples.

All the carbon atom of fullerenes (C60) are equivalent but all C-C bond are not equivalent why ?

In the fullerenes (C60) structure C-C bonds of two different bond length occur at the fusion of two six membered rings the bond length is  C-C = 135.5 pm and at the fusion of  five and six membered rings C-C bond length is 146.7 pm.

Reference: 

STRUCTURE OF FULLERENCES :

Related-topics: 

STRUCTURE OF GRAPHITE: 

STRUCTURE OF DIAMOND :

Silicon Oxide : Silica (SiO2):

What are structural information of Dimomd ?

Related Questions:

What are Silicates ? explain different type of silicates with examples.

Thursday, February 13, 2020

What are most common cyclic meta silicates?

(1) Number of oxygen atoms shared per tetrahedron is 2(Two).
(2) Total number of shared oxygen towards one Si atom is one (1)
(3) In cyclic silicates each tetrahedron shares its two oxygen atoms with other tetrahedron atom such that a cyclo silicates is formed.
(4) General formula is (SinO2n)-2n where n =3, 4,5,6,7 etc 
(5)The most common cyclic polysilicates are the cyclic trimers, (SiO3)36- and the cyclic hexamers (SiO3)612-.
(6) The most common cyclic trimer is Benitoite [BaTi(Si3O9)] and Wollasponite           [Ca3(Si3O9)] 

(7) The most common cyclic hexamer is found in the mineral Beryl [Be3Al2(Si3O9)2] or Be3Al2(Si6O18).



Related Questions:

What are Silicates ? explain different type of silicates with examples.


Wednesday, February 12, 2020

What are the Silicones? Give one example one cyclic Silicone?

Silicones are organosilicon polymeric compounds containing repeated R2SiO units and (-Si-O-Si-) linkage.The name is given silicone because their empirical formula is analogous to that of ketones (R2CO). Silicones may have the cyclic structure also having 3, 4, 5 and 6 nos. of silicon atoms within the ring. Alcohol analogue of silicon is known as silanol.


Sunday, February 9, 2020

Is all the C-C bond length in fullerene is equal ?

"No" In fullerene all the carbon atoms are equivalent but all C-C bond length are not equal . In the fullerene structure C-C bonds of two different bond length occur at the fusion of two six membered rings the bond length is C-C = 135.5 pm and at the fusion of five and six membered rings C-C bond length is 146.7 pm.

Related Questions:

How many six membered ( hexagons) and five membered (Pentagons) carbon ring present in (C60) fullerene ?.

C60 is the most stable fullerene. It has the shape of a football and called buckminsterfullerene. 
C60 consists of fused five and six membered carbon rings. Each six membered rings surrounded by alternatively by hexagons and pentagons of carbon. While the five membered rings are surrounded by five hexagons carbon rings. Thus in C60 fullerene contains 12 five –membered rings and 20 Six –membered rings.

Related Questions:


Saturday, February 8, 2020

What are the hydrolysis products of urea ?

Urea is an organic diamide and is subjected  to hydrolysis by water, the solvent in urine. Water is the nucleophile in the substition and the result it can be visualized as carbonic acid and ammonia .The carbonic acid is unstable and decomposes to carbon dioxide.

Related Questions:

(1) Is all the C-C bond length in fullerene is equal ?












Why CO2 is a gas, but SiO2 is a high melting solid?.

Carbon can form multiple bonds, but silicon cannot. The CO2 molecules is linear with zero dipole moment. Thus, the intermolecular forces are very small and it is a gas at room temperature. SiO2 does not have any multiple bonding in Si-O bond, due to large size of silicon. However, it is a giant 3-D network structure in which each Si is linked tetrahedrally to four oxygen atoms. Hence, it is a stable solid.

Related Questions:

Is all the C-C bond length in fullerene is equal ?