Definition and distinguishing
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Definition and distinguishing
Could someone tell me what sigma and pi bonds are? As well as how to determine if a bond is a sigma or a pi bond. An example would really help, thanks!
Re: Definition and distinguishing
A single bond is a sigma bond. A double bond is a sigma bond plus a pi bond. A triple bond is one sigma and two pi bonds.
A sigma bond is a basic covalent bond, with the bond in line with the bonding orbitals. You can only ever have one sigma bond between any two atoms.
A pi bond is a covalent bond between orbitals perpendicular to the bond direction, usually p-orbitals (never s). The resulting bond is roughly shaped like two croissants with the tips touching at the bonded atoms. Pi bonds do not allow rotation around the bonding axis due to this geometry.
A second pi bond (the third bond in a triple bond, or a second double bond to another atom) is always perpendicular (orthogonal) to the first one. In other words, if the sigma bond is on the x axis, one pi bond will form between orbitals on the y axis and another will form between orbitals on the z axis.
A sigma bond is a basic covalent bond, with the bond in line with the bonding orbitals. You can only ever have one sigma bond between any two atoms.
A pi bond is a covalent bond between orbitals perpendicular to the bond direction, usually p-orbitals (never s). The resulting bond is roughly shaped like two croissants with the tips touching at the bonded atoms. Pi bonds do not allow rotation around the bonding axis due to this geometry.
A second pi bond (the third bond in a triple bond, or a second double bond to another atom) is always perpendicular (orthogonal) to the first one. In other words, if the sigma bond is on the x axis, one pi bond will form between orbitals on the y axis and another will form between orbitals on the z axis.
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Re: Definition and distinguishing
Bonds form between two atoms when:
1. orbital on one atom occupies the same region of space as an orbital on the other atom. When this occurs, the two orbitals overlap.
2. total # of electrons in both orbitals is no more than two
sigma bonds: two atomic orbitals overlap head-to-head
- These are cylindrically symmetric about the bond axis (z-axis)
- example: overlap of 1s orbitals
pi bonds: two atomic orbitals overlap when parallel
-The electron distribution is above and below the bond axis (z-axis)
example: overlap of 2p orbitals
Here is a link for a visual of the overlaps: https://www.chegg.com/homework-help/def ... pi-bonds-6
1. orbital on one atom occupies the same region of space as an orbital on the other atom. When this occurs, the two orbitals overlap.
2. total # of electrons in both orbitals is no more than two
sigma bonds: two atomic orbitals overlap head-to-head
- These are cylindrically symmetric about the bond axis (z-axis)
- example: overlap of 1s orbitals
pi bonds: two atomic orbitals overlap when parallel
-The electron distribution is above and below the bond axis (z-axis)
example: overlap of 2p orbitals
Here is a link for a visual of the overlaps: https://www.chegg.com/homework-help/def ... pi-bonds-6
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- Joined: Fri Sep 28, 2018 12:18 am
Re: Definition and distinguishing
Does the orientation or shape of molecules affect the length of its bonds?
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