About silicon dioxide

[dttom]

We all know that silicon dioxide is in giant covalent structure, and atoms are joined together by strong covalent bonds. While we silicon dioxide dissolves in concentrated sodium hydroxide,SiO2 + 2OH- --> SiO32- + H2O I would like to know the processes involved in detail and how can this be done in molecular level.

 

Beside, it is known that C60 is a very hard material, and it is in sphere shape, I would like to know is there any bond between C60 molecules so that C60 could be observable to our naked eyes (I have not ever seen C60).

[catchem]

We all know that silicon dioxide is in giant covalent structure' date=' and atoms are joined together by strong covalent bonds. While we silicon dioxide dissolves in concentrated sodium hydroxide,SiO2 + 2OH- --> SiO32- + H2O I would like to know the processes involved in detail and how can this be done in molecular level.

[/quote']

 

In the first stage, an adsorbed hydroxy group attacks a surface silicon atom, increasing its electronic density and weakening the Si-O bonds,which are further hydrolyzed with the formation of silanol groups and adsorbed hydroxyl ions.

 

A.G. Okunev et al., Journal of Non-Crystalline Solids 260 (1999) 21

 

Hope this illustration helps. It's always nice to see the curved arrows for a given reaction.

 

/Johannes

[JaKiri]

Beside, it is known that C60 is a very hard material, and it is in sphere shape, I would like to know is there any bond between C60 molecules so that C60 could be observable to our naked eyes (I have not ever seen C60).

 

Van Der Vaals forces, like, well, anything that isn't giant covalent, ionic or hydrogen bonded. However, it is unlikely that there exists enough buckminsterfullerene in the world for it to be visible to the naked eye.

[encipher]

 

 

 

You can also buy a sample of it from here:

 

 

http://www.sciencemall-usa.com/c60buc.html

[JaKiri]

Evidently I didn't count on people producing it in stupidly large amounts for no reason!

[YT2095]

IIRC, LiOH is a Much better reagent to use on SiO2.

 

for what it`s worth anyway