Is molten Boron Trioxide ionic?

  1. I was wondering if Boron Trioxide was melted would it be ionic in the molten state? Boron is not normally ionic except for in some rather rare salts.
     
  2. jcsd
  3. Borek

    Staff: Mentor

    IMHO at 500°C its melting point is way too low for an ionic solid.
     
  4. Nvm I talked with my college chem professor and she said it should act as an ionic substance when liquid.
     
  5. 500 C is not too low for an ionic solid. Ionic just means that it readily disassociates into ionic monomers when liquid instead of dissolved(Like a single Na+Cl- unit for example). And there are covalent compounds that melt at the same temp as NaCl which is approximately 1472 F or 800 C.

    This coordinate compound can be simplified to an ionic compound where the O has a 2- charge and the B has a 3+ charge.

    There are some nonmetal - nonmetal ionic bonds. Normally though that requires polyatomic ions for at least 1 of the charges.

    Boron however is a metalloid so with no polyatomic ions it can form ionic bonds(one of its metal properties) but can also form quite a few covalently bonded molecules(one of its nonmetal properties).
     
    Last edited: Aug 14, 2014
  6. Borek

    Staff: Mentor

    500°C is quite low. Most ionic solids melt at higher temperatures, NaCl that you have mentioned is one of the examples - despite having only a singly charged ions in the lattice it melts at 800°C.

    Al2O3 - which consist of Al3+ and O2- - melts at 2072°C. If boron trioxide were ionic it should melt at even higher temperature, as B is smaller than Al and the inter ionic distances in the lattice would be smaller. If it melts at 500°C its ionic character must be negligible.
     
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