C2H6.. Linear, No?

[babowc]

Isn't C2H6 linear?
I'm on Orgoman Ch7 #35, and HCN is linear, yet C2H6 isn't.

Can anyone explain? 😕

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[topshelf]

HCN is linear because carbon forms a single bond with H and a triple bond with N. So carbon is sp hybridized with ZERO lone pairs, thus, it is linear shape.

In C2H6, if you draw it out, you all the carbon atoms are single bonded to 4 different atoms, making it sp3 hybridized, thus tetrahedral shape.

 

[free99]

HCN is linear because carbon forms a single bond with H and a triple bond with N. So carbon is sp hybridized with ZERO lone pairs, thus, it is linear shape.

In C2H6, if you draw it out, you all the carbon atoms are single bonded to 4 different atoms, making it sp3 hybridized, thus tetrahedral shape.

👍 Nice first post ever, way to pitch in.

These are important to remember. Generally speaking,

4 "neighbors" - sp3 hybridized, tetrahedral, 109 degree bond angles
3 "neighbors" - sp2 hybridized, trigonal planar, 120 degree bond angles
2 "neighbors" - sp hyridized, linear, 180 degree bond angles

"neighbors" includes any lone pairs! which brings up another important point to keep in mind:

H2O and NH3 are common exceptions to the bond angles. In H2O, the O is sp3 hybridized, but the bond angles are more like 104 degrees, because of the electron repulsion from the lone pairs. Same goes for NH3. It isn't necessary to remember exact bond angles, just know that despite being sp3 hybridized, the angles are <109 degrees. Hope this helped!

You may also want to brush up on what the hybridization means in terms of bond strength (s character %age), bond length, and acidity.

 

[joemario]

Why does sulfate ion so3 2- has resonance? Why double bond between an oxygen?

 

[free99]

Why does sulfate ion so3 2- has resonance? Why double bond between an oxygen?

If you draw out the lewis dot structures it'll make sense. remember to add 2 electrons when tallying at first.

 

[joemario]

Thsnk you free 99. But I want to know why 2 extra electrons had to make double bond. The two electrons could have been placed at sulfur as a lone pair???