Advertisement
If you have a new account but are having problems posting or verifying your account, please email us on hello@boards.ie for help. Thanks :)
Hello all! Please ensure that you are posting a new thread or question in the appropriate forum. The Feedback forum is overwhelmed with questions that are having to be moved elsewhere. If you need help to verify your account contact hello@boards.ie

Sigma and Pi Bonding in Benzene...

Options
  • 03-06-2008 8:11pm
    #1
    KeyLimePie
    Closed Accounts Posts: 861 ✭✭✭


    Okee:)
    I'm completely stumped
    As in no clue
    Does anyone know what it's all about?
    And by anyone i mean that ilovechem person :D


Comments

  • Options
    #2
    lovechem
    Closed Accounts Posts: 137 ✭✭lovechem


    :( All I know is: It was thought to be very reactive due to its three triple bonds. But it was however very unreactive is due to delocalised bonding that is present in the benzene ring.

    Sin é. Is it rumoured to be coming up? I hope not :eek:


  • Options
    #3
    Turquoise
    Closed Accounts Posts: 94 ✭✭Turquoise


    Not really, I think if you know that each carbon atom has 3 sigma bonds, and it's fourth electron is delocalised and located in a p orbital, with each of the p orbitals overlapping sideways - you should get the marks. Then something about these overlapping orbitals making two doughnut shape rings, forming a pi bond. The book goes into a little more but I'm not sure they'd ask anything that complex.
    Though if somebody could explain it it'd be great, I'm not sure how the examiner will feel if I start rambling about doughnuts. Lol!


  • Options
    #4
    ZorbaTehZ
    Registered Users Posts: 2,149 ✭✭✭ZorbaTehZ


    Essentially you've 6 carbon atoms, and they undergo sp2 hibridization. There are 3 σ-bonds - 1 with either adjacent carbon atom, and 1 with the hydrogen atom. You also have an unhibridized p-orbital perpendicular to the ring on each carbon atom. These combine to create a delocalized π-cloud above and below the ring.


  • Options
    #5
    lovechem
    Closed Accounts Posts: 137 ✭✭lovechem


    I have actually never heard that ^^ in my life. This time tmw, I'll just be absolutely TERRIFIED.


  • Options
    #6
    Turquoise
    Closed Accounts Posts: 94 ✭✭Turquoise


    I've never heard the hibridization malarky....I'm just sticking with what I've got and hoping for the best! :(


  • Advertisement
  • Options
    #7
    sso
    Registered Users Posts: 105 ✭✭sso


    Don't panic. The basics are: The carbons are bonded in the benzene ring by strong sigma bonds. Each carbon atom also connects to one Hydrogen by a sigma bond. Each carbon therefore has 3 sigma bonds - 2 to its nearest carbons and 2 to a hydrogen. The 4th bond the Carbon has to make is a pi bond. There are three of these in each ring. They move slightly away to form a ring of electrons in the centre giving extra strength. This is called a dislocated pi bond.

    Good luck


  • Options
    #8
    salman85
    Closed Accounts Posts: 135 ✭✭salman85


    theres an easier answer

    there are sigma bonds with the carbons on either side and there are 6 delocalised electrons which help stablize the compound forming a pi bond the ring is therefore hard to break and it is soluble cyclohexane but un soluable in water because it is non polar and it doesnt undergo addition reactions

    everything you need to know about benzene


Advertisement