1
$\begingroup$

Why does $\ce{CO2}$ make two π bonds? Why can't it make four σ bonds? Also, why do the π bonds not involve for repulsion?

$\endgroup$
2
  • $\begingroup$ "not involve for repulsion" What is that even supposed to mean? $\endgroup$
    – Mithoron
    Commented May 6, 2017 at 20:40
  • $\begingroup$ that means, according to the vsepr theory sigma bonds and lone electrons are the main reason for detect the shape of the molecule. Then that should be only sigma bonds and lone electrons are only the reason for repeal. Why pi bonds are not involving for that? $\endgroup$ Commented May 7, 2017 at 3:02

2 Answers 2

6
$\begingroup$

Recall the definition of σ-bonds. They are caused by the head-on overlapping of the orbitals.

enter image description here

$s$ orbitals always, and only form σ-bonds while the $p$ orbitals in the direction of bond axis (which is $p_x$), also form σ-bonds.

The other two $p$ bonds cannot form σ-bonds as they are perpendicular to the bond axis, and cannot overlap head-on. In such cases, π-bonds are formed, by the sideways overlapping of the orbitals.

enter image description here

The $p$ bonds not perpendicular to the bond axis involve in π-bond formation ($p_y$ and $p_z$).

$\endgroup$
1
  • $\begingroup$ @OsalSealaka Please dont use comments to say thanks. If this answer satisfies you, click the tick button. That lets everyone know you got an answer. $\endgroup$ Commented May 8, 2017 at 2:59
0
$\begingroup$

Actually σ bonds are formed when two hybridised orbital of two adjacent atoms overlap each other.

So considering an atom, there can be one orbital along one axis that would be overlapping with another while the other orbital may find a parallel orbital of adjacent atoms and for π bond so same is the case of $\ce{CO2}$.

$\endgroup$
0

Not the answer you're looking for? Browse other questions tagged or ask your own question.