Is C2H4 an Example of SP2 Hybridization?

[lokobreed]

In my take home study guide it says that C2H4 is an example of an SP2 hybridization... but when I draw out the electronic geometry I do not get a SP2 hybridization... am I doing something wrong or is my handout incorrect.

I get C2H2 as being an example of an SP2 hybridization

 

[dextercioby]

Well, why would you say that the 2 C-atoms in acetylene are in sp_2 hybrid state ? As far as I know, they have a very stable triple bond between them and this is an sp hybridization.

Ethene C_2 H_4 has the 2 atoms of C in sp_2 hybrid state, as the bond between them is double.

These facts are high-school textbook material, though an explanation in terms of quantum mechanics is usually given in university.

 

[lokobreed]

perhaps i just don't understand this ... but wouldn't
H H
| |
H-C=C-H be 5 groups total or are you just counting each central atom by itself thus each C would have 3 groups resulting in an SP2 hybridization?

 

[dextercioby]

We're not on the same page. The C-atoms must have 4 bounds in all (because they must gather 8 electrons in the vecinity of their nucleus to get the most stable configuration), so that the structural formula for ethene MUST be H_2 C = CH_2. I don't know what you mean by groups.

 

[lokobreed]

right but as in groups i am saying that the double bond between the C=C is looked as one group not 2...

 

[cdotter]

right but as in groups i am saying that the double bond between the C=C is looked as one group not 2...

Either carbon has three bonds: a bond to a hydrogen, a bond to a hydrogen, and a double bond to the other carbon. They're all counted as one, regardless of whether they're single, double, or tripe. 1+1+1=3=sp2 hybridized.

 

[DrDu]

Whether ethylene is described in terms of sp2 or sp3 hybrids is a matter (as in most molecules) of taste, see e.g. or google for "banana bonds":
http://www.google.de/imgres?imgurl=...de&gbv=2&tbs=isch:1&ei=dJiQTdCvOcqEhQfflLzGDg

P.S.: The chemistry or the atomic, solid state, computational physics forums seem more appropriate for this question.