This has always confused me.
An example would be great.
Yes this is basic stuff, sorry for wasting your time.
An example would be great.
Yes this is basic stuff, sorry for wasting your time.
What exactly does it mean to "donate an electron pair?"
- Thread starter JDAD
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Donating e- pair basically refers to the lewis base....simply put that when this molecule forms a bond it donates both e- in the pair b/w the bonds. Classic example in NH3. The N has two lone pairs that it can donate to form a coordinate covalent bond. It can form a bond with...BH3 which has no lone pairs. This stuff usually get me too but I just keep track of it by lone pairs. If it ain't got lone pairs it can't donate it or act as a lewis base/ligand.
Hope this helps.
Hope this helps.
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Donating e- pair basically refers to the lewis base....simply put that when this molecule forms a bond it donates both e- in the pair b/w the bonds. Classic example in NH3. The N has two lone pairs that it can donate to form a coordinate covalent bond. It can form a bond with...BF3 which has no lone pairs. This stuff usually get me too but I just keep track of it by lone pairs. If it ain't got lone pairs it can't donate it or act as a lewis base/ligand.
Hope this helps.
Hope this helps.
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my take on it was this way...
Ionic bonds are really greedy. In something like NaCl, Cl REALLY wants that extra electron, and Na would really like to get rid of it. So Cl essentially takes Na's extra electron, making Na+Cl- (an ionic bond.)
Covalent bonds are when they are content with just sharing their electrons. This goes for any C-O or C-H bonds. H would like another electron, but isn't as crazy about it as Cl, so if H gets Cl's electron sometimes, and Cl gets H's electron sometimes, they are content. Same with Carbon and its bonds. It isn't electronegative enough to completely steal the electron (a la ionic bond) but is content sharing its electrons in 4 bonds, as long as the electrons are being shared, and it gets the other atom's electron occasionally too.
In covalent bonds, the 2 electrons involved in the bond are kinda floating inbetween the 2 sharing atoms.
Ionic bonds are really greedy. In something like NaCl, Cl REALLY wants that extra electron, and Na would really like to get rid of it. So Cl essentially takes Na's extra electron, making Na+Cl- (an ionic bond.)
Covalent bonds are when they are content with just sharing their electrons. This goes for any C-O or C-H bonds. H would like another electron, but isn't as crazy about it as Cl, so if H gets Cl's electron sometimes, and Cl gets H's electron sometimes, they are content. Same with Carbon and its bonds. It isn't electronegative enough to completely steal the electron (a la ionic bond) but is content sharing its electrons in 4 bonds, as long as the electrons are being shared, and it gets the other atom's electron occasionally too.
In covalent bonds, the 2 electrons involved in the bond are kinda floating inbetween the 2 sharing atoms.
Thanks, but that doesn't answer my question.
In a regular covalent bond where each atom gives an electron, can there be a "donating of an electron pair"?
Or what about OH- We know it is a base, therefore it must donate an electron PAIR, but it doesn't have an electron pair to donate? And that means H+ isn't able to accept an electron PAIR like an acid. If we think of H+ as H3O+, it still isn't accepting an electron pair, it is just donating an H.
Same thing with HCL, we know it is a Lewis acid, therefore if must accept an electron pair. How does it do this?
Will someone clear this up please
In a regular covalent bond where each atom gives an electron, can there be a "donating of an electron pair"?
Or what about OH- We know it is a base, therefore it must donate an electron PAIR, but it doesn't have an electron pair to donate? And that means H+ isn't able to accept an electron PAIR like an acid. If we think of H+ as H3O+, it still isn't accepting an electron pair, it is just donating an H.
Same thing with HCL, we know it is a Lewis acid, therefore if must accept an electron pair. How does it do this?
Will someone clear this up please
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It does have an electron pair to donate though, as indicated by the -.
When it was H2O, and the H was ripped off, just the Proton left, making H+ and the H's electron stuck with the H2O. So the OH- recieved both electrons from that old bond.
It doesnt really donate the ENTIRE electron pair, rather, puts it to use in a covalent bond. It can donates those 2 extra electrons into making a bond with a poor H+ who has no electrons at all.
Now the HCl part i'm not as sure about. I like to go about my acids and bases bronsted/lowry style, because it is easier to visualize. Especially in the HCl + H2O example.
When it was H2O, and the H was ripped off, just the Proton left, making H+ and the H's electron stuck with the H2O. So the OH- recieved both electrons from that old bond.
It doesnt really donate the ENTIRE electron pair, rather, puts it to use in a covalent bond. It can donates those 2 extra electrons into making a bond with a poor H+ who has no electrons at all.
Now the HCl part i'm not as sure about. I like to go about my acids and bases bronsted/lowry style, because it is easier to visualize. Especially in the HCl + H2O example.
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OH- does donate an electron pair, just like NH3 does. When either of these species "accept" a proton, they donate both of the electrons that form the new O-H or N-H bond. The proton (H+) had no electrons to begin with, so both of the electrons in that bond had to come from the oxygen or nitrogen. Take the example of a lewis acid and base, if NH3 (2 nonbonded electrons) donates a lone pair to AlCl3 (no extra electrons), the new compound is
Cl3Al-NH3. In this case, NH3 donated a lone pair. Such a bond is called coordinate covalent when both electrons come from the same species.
Cl3Al-NH3. In this case, NH3 donated a lone pair. Such a bond is called coordinate covalent when both electrons come from the same species.
another area this is related to is in redox reactions. there you look at one of the atoms and compare its oxidation state before and after the reaction. the difference in oxidation number will indicate if it accepted or donated e-'s. this technique can be used in that HCl example but it takes a bit longer to do.
I'm not exactly sure this is correct because I don't really remember this stuff that well and I'm too lazy to look it up, but I think in a coordinate covalent bond both e-'s of the bond are donated by one atom, rather than in the case of CH4 where the e- are used from both atoms, C and H. NH3 is a good example of a coordinate covalent bond because N has a lone pair of e- H H
l l
H-N: + B-H
l l
H H
and it can donate both of those e- to a molecule such as BH3 which can accept a pair of e-. By donating both of the e-'s a coordinate covalent bond is formed. Also, since NH3 donates a pair of e-'s it is considered a Lewis base because it donates e-'s, and BH3 would be a lewis acid because it accepts a pair of e-'s.
In a covalent bond the e-'s would not be donated, they would be shared. For example, in H2 each H atom has one e- (not pair, just one e-)
. .
H + H = H:H the two electrons can be shared by both atoms.
In an ionic bond, the bond is formed between two atoms when one or more electrons are transferred from the valence shell of one atom to the valence shell of the other, as in NaCl where Na becomes the cation Na+ and Cl becomes the anion Cl-.
I hope this helps and I'm not sure that this is exactly correct but someone might want to clarify this.
l l
H-N: + B-H
l l
H H
and it can donate both of those e- to a molecule such as BH3 which can accept a pair of e-. By donating both of the e-'s a coordinate covalent bond is formed. Also, since NH3 donates a pair of e-'s it is considered a Lewis base because it donates e-'s, and BH3 would be a lewis acid because it accepts a pair of e-'s.
In a covalent bond the e-'s would not be donated, they would be shared. For example, in H2 each H atom has one e- (not pair, just one e-)
. .
H + H = H:H the two electrons can be shared by both atoms.
In an ionic bond, the bond is formed between two atoms when one or more electrons are transferred from the valence shell of one atom to the valence shell of the other, as in NaCl where Na becomes the cation Na+ and Cl becomes the anion Cl-.
I hope this helps and I'm not sure that this is exactly correct but someone might want to clarify this.
Im sorry for the above post. I made the bonds and the e- dots perfectly aligned to the atoms but when I hit post message it got changed. So, Im sorry if the drawings are messed up, but I tried to edit it and it's still the same.
