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    When you react tin with iodine directly, when is \mathrm{SnI_2} formed and when is \mathrm{SnI_4} formed? The best I could find is this: http://alpha.chem.umb.edu/chemistry/...Projection.pdf

    "Direct reaction of tin metal with iodine in methylene chloride yields \mathrm{SnI_4} as the principal product, with formation of \mathrm{SnI_2} as a side reaction."
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    SnI4 is considerably more stable than SnI2 because the energy for the promotion of a 5s electron to a 5p orbital (to get sp3 hybridisation) is compensated by the formation of two new Sn-I bonds. So SnI4 is lower in energy than SnI2 so for this reason, you'd always get SnI4 as your major product from the simple reaction of tin with iodine. You'd need more specialised conditions to get SnI2 but off the top of my head I don't know what they would be.

    The opposite would be true for direct reaction of lead with iodine. The energy gap for promotion of 6s to 6p is larger than the energy got back from the formation of two Pb-I bonds so PbI2 would be the major product.
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    (Original post by Kyri)
    SnI4 is considerably more stable than SnI2 because the energy for the promotion of a 5s electron to a 5p orbital (to get sp3 hybridisation) is compensated by the formation of two new Sn-I bonds. So SnI4 is lower in energy than SnI2 so for this reason, you'd always get SnI4 as your major product from the simple reaction of tin with iodine. You'd need more specialised conditions to get SnI2 but off the top of my head I don't know what they would be.

    The opposite would be true for direct reaction of lead with iodine. The energy gap for promotion of 6s to 6p is larger than the energy got back from the formation of two Pb-I bonds so PbI2 would be the major product.
    Heating tin with iodine in 2M HCl should give SnI2 as brilliant red needles
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    (Original post by Kyri)
    SnI4 is considerably more stable than SnI2 because the energy for the promotion of a 5s electron to a 5p orbital (to get sp3 hybridisation) is compensated by the formation of two new Sn-I bonds. So SnI4 is lower in energy than SnI2 so for this reason, you'd always get SnI4 as your major product from the simple reaction of tin with iodine. You'd need more specialised conditions to get SnI2 but off the top of my head I don't know what they would be.

    The opposite would be true for direct reaction of lead with iodine. The energy gap for promotion of 6s to 6p is larger than the energy got back from the formation of two Pb-I bonds so PbI2 would be the major product.
    Ah thanks.
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    (Original post by cpchem)
    Heating tin with iodine in 2M HCl should give SnI2 as brilliant red needles
    Hydrolysis?
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    (Original post by cpchem)
    Heating tin with iodine in 2M HCl should give SnI2 as brilliant red needles
    Ah cool . I didn't realise it would be quite that straightforward.
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    (Original post by Kyri)
    Ah cool . I didn't realise it would be quite that straightforward.
    When in doubt, consult G&E
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    (Original post by cpchem)
    When in doubt, consult G&E
    What's G&E? :confused:
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    (Original post by Kyri)
    What's G&E? :confused:
    The Chemistry of the Elements, by Greenwood and Earnshaw. It's basically the bible of inorganic chemistry
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    (Original post by cpchem)
    The Chemistry of the Elements, by Greenwood and Earnshaw. It's basically the bible of inorganic chemistry
    Two of my old profs at Leeds Uni...

    Norman's course on boranes still gives me nightmares ... is decaborane five times more borane than diborane?
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    (Original post by cpchem)
    The Chemistry of the Elements, by Greenwood and Earnshaw. It's basically the bible of inorganic chemistry
    Ah right. We were always recommended the big Inorganic Chemistry books by Shriver and Atkins as well as the one by Housecroft and Sharpe but that one you mentioned seems pretty good.
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    Haha... I never bothered with boron chemistry. I suspect all those clusters would have given me a headache.
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    (Original post by cpchem)
    The Chemistry of the Elements, by Greenwood and Earnshaw. It's basically the bible of inorganic chemistry
    hey hey, coupled with cotton and wilkinson.
 
 
 
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