Carbon vs Silicon

[albertlee]

We know that carbon always exist in covalent bond with itself or other elements.

 

 

But, how about Silicon? is silica a convalent or ionic compound?

[RyanJ]

I'm not shure but I think its the same for Silicon but as its in the metalloids group then it may be able to form ionic bonds.

 

Cheers,

 

Ryan Jones

[Skye]

Silica is covalent, but remember it is silicon dioxide. What you probably mean are polysilanes, which are like alkanes with silicon in the place of carbon.

[insane_alien]

polysilanes are very unstable due the larger size of a silicon atom and will spontaneously combust in air. useless factoid but there you go.

[albertlee]

Wow...

 

does silica have high melting point?

 

It looks to me as an ionic compound...

 

btw, are all crystals covalent?

[woelen]

Wow...

 

does silica have high melting point?

 

It looks to me as an ionic compound...

 

btw' date=' are all crystals covalent?[/quote']

Silica has quite a high melting point. I do not remember precisely, but you need several hundreds of degrees centigrade in order to melt it.

 

Many crystalline compounds are covalent (e.g. sugar), but there also are many ionic crystalline compounds (e.g. table salt, which contains Na(+) ions and Cl(-) ions in a 1:1 ratio).

 

Compounds can be both ionic and covalent. As an example take sodium sulfate, Na2SO4. This consist of Na(+) ions and SO4(2-) ions in a 2:1 ratio, so the overall structure is ionic. Inside the SO4(2-) ion, the bonds are covalent. So, a more complicated ion, consisting of more than 1 atom frequently is covalent and such an ion can be regarded as a covalent molecule with some non-zero charge. Examples of these are SO4(2-), CO3(2-), ClO3(-), NH4(+), but there are many many many more.