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# Oxidation numbers! watch

1. Ni(CO)4
What are the oxidation numbers on each element?

I don't know about C or Ni so I'm stuck

Also...

1) Peroxides have oxy. no. of -1. Why is H202 a peroxide and not NO2? Is it because peroxides must have a single c-c bond?

2) What is a superperoxide? My teacher says they have a -1/2 oxidation no.
2. (Original post by Phalange)
Ni(CO)4
What are the oxidation numbers on each element?

I don't know about C or Ni so I'm stuck

Also...

1) Peroxides have oxy. no. of -1. Why is H202 a peroxide and not NO2? Is it because peroxides must have a single c-c bond?

2) What is a superperoxide? My teacher says they have a -1/2 oxidation no.
CO is carbon monoxide, itself has zero charge. You are probably missing the supposed 2+ for the compound Ni(CO)4, which is really Ni2+.
- If that is not the case, then, usually oxygen is taken as -2, see if you can work something out from there.

1) a peroxide comes from the fact that it is the O-O bond. ie H-O-O-H
this is the peroxide bond. NO2 is nitrogen dioxide, O=N=O, not a peroxide. peroxide doesn't have carbon, so no C-C bond.

superoxide is an anion of oxygen with the chemical formula O2-.
2 is a superscript.

Hence, 2(oxygen charge) = -1 so each oxygen has -1/2 charge
3. (Original post by shengoc)
CO is carbon monoxide, itself has zero charge. You are probably missing the supposed 2+ for the compound Ni(CO)4, which is really Ni2+.
- If that is not the case, then, usually oxygen is taken as -2, see if you can work something out from there.

1) a peroxide comes from the fact that it is the O-O bond. ie H-O-O-H
this is the peroxide bond. NO2 is nitrogen dioxide, O=N=O, not a peroxide. peroxide doesn't have carbon, so no C-C bond.

superoxide is an anion of oxygen with the chemical formula O2-.
2 is a superscript.

Hence, 2(oxygen charge) = -1 so each oxygen has -1/2 charge
Thank you for that
Um no it doesn't say the Ni compound has any charge at all. Maybe a typo. I'll ask my teacher tomorrow.
4. (Original post by Phalange)
Thank you for that
Um no it doesn't say the Ni compound has any charge at all. Maybe a typo. I'll ask my teacher tomorrow.
Ni has 8 electrons in its d orbitals, couples with those 8, 2 from each CO as ligand donor, That would be 16 electrons, short of the "holy grail" 18 electron rule for stable TM complex.

5. (Original post by shengoc)
Ni has 8 electrons in its d orbitals, couples with those 8, 2 from each CO as ligand donor, That would be 16 electrons, short of the "holy grail" 18 electron rule for stable TM complex.

Don't forget that in complex, transition metal electrons invariably sit in the valence d-orbitals in preference to the s-orbitals, so Ni0 is d10. Adding the 8 carbonyl electrons gives you the desired 18.
6. (Original post by -Kav-)
Don't forget that in complex, transition metal electrons invariably sit in the valence d-orbitals in preference to the s-orbitals, so Ni0 is d10. Adding the 8 carbonyl electrons gives you the desired 18.
ah, it is the desired "holy grail" after all, that is what our tutor likes to call it!
7. (Original post by shengoc)
CO is carbon monoxide, itself has zero charge. You are probably missing the supposed 2+ for the compound Ni(CO)4, which is really Ni2+.
As you quite correctly state the carbonyl ligand is neutral so that the oxidation state of Ni in Ni(CO)4 is zero.

This is one of the (few) cases where a TM takes a zero oxidation state.

On another note, this compound is important in the Mond process for purification of nickel.

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