[化學] 碳雙鍵一問

the electron density in C=C bond is much higher than C-C, that's true!

this is because you have made some mistakes in your understanding

the orbital 2px forming the double bond is not empty, instead, each of

the 2px orbital has one electron

so when this two 2px orbital overlap, πbond is formed. so π bond

consists of two nuclei and two electron

together with the bonded paired of electron in σ bond, so the electron density of C=C bond is very high~~!!!!!

2. I wonder if we should say the pi bond is in 2py instead of 2px,
because the sigma single bond is already in the x-orientation.
So, I think it is more appropriate to say the pi bonded electrons is
in 2py. Does that make sense?

it depends on how you define the axis

2009-05-17 02:32:26 補充：
By the way, s-orbital is spherical. So it doesn't matter whether it is px or py or pz which forms the pi bond.

a single s-orbital cannot forms pi bond

Actually the p-orbitals are more diffused and exposed, as a result, they are more available for attacking molecules.

By the way, s-orbital is spherical. So it doesn't matter whether it is px or py or pz which forms the pi bond.

to supplement the answer:

1. density: we know density is mass / volume
so electron density should be interpreted as
number of electrons / unit space

in a C=C, there are four bonded electrons between the two C nuclei
when you compare that with a C-C sigma single bond,
you will see that the electron density is higher, isn't it?

2. I wonder if we should say the pi bond is in 2py instead of 2px,
because the sigma single bond is already in the x-orientation.
So, I think it is more appropriate to say the pi bonded electrons is
in 2py. Does that make sense?