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Iodine electrode?

  1. Feb 10, 2007 #1
    In a battery cell, let iodine (I2) be the oxidant. In this half cell, what could the electrode be? Could it have an I2(solid) coating so when it accepts electrons, it will form iodide and fall into the solution? I recall I2 was a solid. But what physical form would iodide (I-) be? It will try to bind with positive charges very quickly which exists in the solution? Or it could be that the positive charge exists in the salt bridge and postive ions migrate towards this half cell and the newly formed I- will travel down the electrode to combine with the positive ion.

    Or should the electrode be graphite and both iodine and iodide be in the solution? But I2 will form a precipitate? Does it matter?
    Last edited: Feb 10, 2007
  2. jcsd
  3. Feb 12, 2007 #2


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    The "iodine" electrode could be anything conductive that is compatible with water, iodide and iodine. At the anode, iodine would accept electrons from the cathode material (zinc?) via the conductor (electrode and wire) and would be reduced to iodide.

    A reasonable form of iodine would be triiodide.

    I2 + I- ----> I3- (brown)
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