system
Given the following post, respond as if you're commenting on Reddit:
human
Why is the central carbon atom in Allene not hybridized?

Took a chemistry test today, and got stumped by this question. I figured it would be hybridized given the double bonds on both sides. I know Allene has a "twist" in the figure at the hydrogen ends, but I can't figure out why the central C atom isn't hybridized even though it has sigma and pi bonds on either side of it. I also attempted to google this, but every site says it is in fact hybridized. Help?
gpt
I believe the test may have been wrong. The two end carbons are both sp2 hybridised, and the middle carbon is sp hybridised. This sp hyrbridisation arises because the molecule is linear (due to the two double bonds) and undergoes the equivalent hybridisation of an alkyne. The 2s orbital on the middle carbon overlaps with only the 2px p orbital leaving the others to form the pi bonds.