What is the chemical name for OI2?

  1. 1. The problem statement, all variables and given/known data
    What is the chemical name for OI2? Does Nickel have more than one charge like most other transition metals?

    I think the name for OI2 is Oxygen diiodide. This sounds really weird. How about other instances if there are I3,I4,I5 or even I6 in a covalent compound?
    One of my bks says it does while another says it does't.
    Last edited: Oct 11, 2008
  2. jcsd
  3. Borek

    Staff: Mentor

    Re: Nomenclature

    Oxygen diiodide sound soK to me, but English nomenclature is not my forte.

    Ni(II) is the most stable, other oxidation states were definitely observed but are rare.
  4. symbolipoint

    symbolipoint 3,194
    Homework Helper
    Education Advisor
    Gold Member

    Re: Nomenclature

    The oxidation state of Oxygen can easily be inferred knowing that the charge of the I will be negative one. Best guess is that compound you show is called oxygen iodide.

    For other reduction states of Nickel maybe try looking in a table of electromotive series (reduction tables). Do you find any Nickel ions other than Nickel(II) ?

    Borek, do you if there are other compounds of only Oxygen and Iodine which have different ratios?
  5. Borek

    Staff: Mentor

    Re: Nomenclature

    On the second thought - I would rather go for diiodine oxide. Oxygen is more electronegative.

    Note, that the effect may depend on the tables used. Some of my books list only Ni2+. Do not mistake absence of evidence for the evidence of absence :smile:

    Several. I2O4, I2O5, I2O7, I4O9 (first two are listed in several books, last two - each in one book only, no idea what it means). Interestingly, none of those books lists I2O.

    Note: apart from translated Sienko/Plane, all other books I have consulted were published only in Polish.
  6. Re: Nomenclature

    Thank you but I've not learnt about oxidation states yet. However, I've read before that in a compound, the element that is more to the left in the periodic table or, if both are in the same group, then the one that is higher is written first. Is my resource right? As for nickel, the conclusion being made is that Nickel is similar to Zinc, in having only one possible charge. Am I right?
  7. Borek

    Staff: Mentor

    Re: Nomenclature

    Only approximately. To some extent that's the way electronegativity of elemnets changes in the periodic table. It will work in most cases, but not for compounds of oxygen and halogens.

    From Principles of Chemical Nomenclature, A GUIDE TO IUPAC RECOMMENDATIONS, section 4.2 BINARY-TYPE NOMENCLATURE, subsection 4.2.2 Name derivation (page 28):

    So there is oxygen fluoride, but chlorine, bromium and iodine oxides.

    Again, it depends where you check. Simplified sources claim that Ni forms only Ni2+ cations, real chemistry books list several other cations. There are not many compounds where nickel has valence other than II, but there is no doubt they exist.
  8. Re: Nomenclature

    Ok, thank you for your replies.
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