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Is SiO3 soluble in Hydrofluoric acid?

  1. Aug 20, 2011 #1
    Is SiO3 soluble in Hydrofluoric acid???

    Is SiO3 soluble in Hydrofluoric acid???

    Why am I asking this: I have some crystals of Be3Al2(SiO3)6 - Beryl
    and there are structural channels which I want to enlarge...! (I know it sounds impossible)

    Here is how the crystal's structure looks like: http://youtu.be/-kS4zWyYLJk" [Broken]
    The structural channels are sorrounded by SiO3 rings... So I was wondering if SiO3 is soluble in HF or not? If it is I could try immersing the crystal into HF for a very short interval to cause a little enlargement of the channels and avoiding much damage to the bulk of the crystal

    Thanks in advance :)
     
    Last edited by a moderator: May 5, 2017
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  3. Aug 23, 2011 #2

    chemisttree

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    Re: Is SiO3 soluble in Hydrofluoric acid???

    So you are trying to move those SiF4 molecules through the channels that are only barely large enough for water?
     
  4. Aug 25, 2011 #3
    Re: Is SiO3 soluble in Hydrofluoric acid???

    Actually I am willing to increase the diameter of these channels.

    The channel is caused by a ring of Si6O18 and I do know that beryl is solluble in HF.

    But the question is which part of the xtal dissolves in HF first??? Is it possible to immerse the crystal in HF for a very short interval so that some of the HF enter the channels before the rest of the outer crystal is dissolved...?

    Thanks in advance
     
  5. Aug 25, 2011 #4

    chemisttree

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    Re: Is SiO3 soluble in Hydrofluoric acid???

    The accessible parts dissolve first. Think about what you want to happen. You want HF to get into a channel already occupied by water molecules. That channel is barely large enough to contain said water. After the HF sneaks by the water, you want it to react with silica to produce SiF4. Maybe you don't know that this is how silica "dissolves" in HF? Note that you will need 4 HF molecules per molecule of silica. After that you want the substantially larger SiF4 molecule to find its way past water molecules, incoming HF molecules and other SiF4 molecules just milling around.

    Sounds like a very slow process to me. It's much more likely that the silica at the surface of the beryl will dissolve away leaving a network of alumina barely holding on if at all. The alumina goes away, exposing fresh silica which is attacked by more HF. This continues until.......

    Do you have any information that HF can preferentially strip silica from the crystal of beryl without utterly destroying it? If you do, I'm interested as well.
     
  6. Aug 25, 2011 #5
    Re: Is SiO3 soluble in Hydrofluoric acid???

    Is this even possible theoretically???
     
  7. Aug 26, 2011 #6

    chemisttree

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    Re: Is SiO3 soluble in Hydrofluoric acid???

    I don't think so. Both the Alumina and Silica phases are soluble (reactive) in HF. It would need to be a pretty exotic material IMO.
     
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