我想問關於碳的特性

碳最多form 4 個bond.
響你個例子入面, graphite 同 fullerene 有三粒electron form covalent bonds, 另外有一粒你睇唔到, 因為做咗delocalisation, 響planar structure 上面遊走.

你識得fullerene 就估你係CE 以上程度.
three electrons hydridize to form sp2-hybridization, yielding 3 C-C bonds;
one electron keeps un-hybridized and stay in p-orbital (pz orbital) perpendicular to C-C plane. the sideway overlap of p-orbitals from each C-atom gives pi-bond over whole plane.

簡單講, 可以想像成一個double bond 同兩個single bond, 但係double bond 入面其中一個bond 會四圍走.
graphite 係一層層由benzene 黐埋一齊嘅plane 組成, double bond 四圍走;
fullerene 嘅delocalised electron 就響球體表面走.

C form 兩個double bond 亦有, 不過少; 呢種叫allene. 例子有propadiene.
唔穩定加上有掌性 (chiral), 未到A-Level 都唔會教, 因為教起上黎太麻煩.


2010-09-12 01:28:49 補充：
thanks user "知識就是力量" for his kind remark. in fact, i know little for 3-3-4's syllabus.
but i heard that s-p-d-f orbitals will NOT be taught nowadays, is it?
if so, then it could be difficult to explain...

2010-09-14 11:37:27 補充：
Ｃ－Ｃ＝Ｃ　　　　　　Ｃ＝Ｃ－Ｃ　　　　　Ｃ－Ｃ－Ｃ
　　｜　　　　　　　　　　｜　　　　　　　　　 ||
　　Ｃ　　　　　　　　　　Ｃ　　　　　　　　　Ｃ
你見到double bond 入面其中有條bond 可以走去第二到

A carbon atom can form 4 bond but not 3 bond.
Methane structure:
　　H
　　|
H - C - H
　 |
　 H

己式庚辛:
fullerene is not only in CE level now.
It also becomes a DSE level learning in F5 =)

2010-09-12 11:18:51 補充：
I still haven't met s-p-d-f orbitals yet. So I don't know will this part be taught in the future. If I have chance, I may tell u.