Why carbon?

[JustinM.Dragna]

I've taken a decent amount of organic chemistry courses as an undergraduate, and the one question that was never touched on is, why does carbon form so many compounds? Does anyone have a good answer to this?

[AtomicMX]

Because it has 4 electrons to share...

[AtomicMX]

Silicon its supposed to be able to from as many compounds as carbon but.. in very very speciall conditions...

[AtomicMX]

and because it can make nets of itself...

[JustinM.Dragna]

Silicon its supposed to be able to from as many compounds as carbon but.. in very very speciall conditions...

 

do you have a link to some information on this?

 

what exactly do you mean by "form nets with itsself?"

[budullewraagh]

there's a trend for group 14 elements; they are all able to form many compounds, but as you go down, they form less compounds. the reason carbon is so versatile is because it has 4 valence electrons, and thus can form 4 bonds and perhaps more, depending on if something is to create coordinate covalent bonds, although carbocations are extremely unstable and only can exist for long periods of time (more than 1/100 second) when in a solution of 50% HF:SbF5

C forms "nets". ever notice how graphite and diamond are both pure carbon? what makes them different is their structure. they form large patterns.

[JustinM.Dragna]

there's a trend for group 14 elements; they are all able to form many compounds' date=' but as you go down, they form less compounds. the reason carbon is so versatile is because it has 4 valence electrons, and thus can form 4 bonds and perhaps more, depending on if something is to create coordinate covalent bonds, although carbocations are extremely unstable and only can exist for long periods of time (more than 1/100 second) when in a solution of 50% HF:SbF5

C forms "nets". ever notice how graphite and diamond are both pure carbon? what makes them different is their structure. they form large patterns.[/quote']

 

 

yes, carbon forms nets with itself, but why? And it having four electrons is only part of the argument for why it forms so many compounds. Otherwise, all group 4A elements would be embedded in everything. However, someone else mentioned that silicon can form just as many compounds under special conditions, but i can't find any literature on it yet. If anyone can send a good link to this subject, i would greatly appreciate it.

[budullewraagh]

it can't.

[Crash]

the sp orbital hybridising allows it to have four bonds, to awnser the first question

 

as for silicon its jsut as good at competing with carbon, that is why super conductors are made out of silicon ceramics because it has mettalic propertys like carbon, the net thing is just the 2D lattice strucutre it forms as opposed to a continuos network

[AtomicMX]

exactly.

[Crash]

nice contribution.............

 

Also they have many structural isomers because of there many bonds, aswell as being able to form very large molecules due to the four bonds/bonding to themselves and other nice characteristics

[budullewraagh]

the sp orbital hybridising

sp^3 to be exact

[apathy]

that's exactly it

the s and p orbitals of carbon are relatively close in energy

it isn't so tough for them to hybridize

in Si, the 3p orbitals are higher energy and more diffuse than carbons 2p orbitals

 

this (and the 1/2 filled octet) is mainly why carbon can form chains and "nets" as they were called earlier

silicon can form chains sometimes, like in polysilanes

but the Si-Si bonds (226 kJ/mol) are weaker than the C-C bonds (348 kJ/mol)

 

as a side note on polysilanes, they typically exhibit delocalized sigma bonds alongthe backbone, this is weird because most delocalized orbitals are pi, but the sigma orbitals in Si-Si chains are diffuse enough to overlap and cause some delocalization

 

Edit:

Came across this a second time and would like to add that I did not mean to imply that the s and p orbitals of Si are unable to hybridize as, of course, they do.