Is SiO3 soluble in Hydrofluoric acid?

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SiO3 is not soluble in hydrofluoric acid (HF) in a way that would allow for controlled enlargement of structural channels in beryl crystals (Be3Al2(SiO3)6). While beryl itself is soluble in HF, the dissolution process tends to affect the accessible surfaces first, potentially leading to the loss of structural integrity rather than the desired selective enlargement of channels. The reaction of silica with HF produces SiF4, but this process is complicated by the presence of water molecules in the narrow channels, making it difficult for HF to penetrate effectively. The consensus is that immersing the crystal in HF, even for a short duration, is likely to result in the dissolution of both silica and alumina phases, which could compromise the crystal's structure rather than enhance it. Theoretical discussions suggest that preferentially stripping silica without damaging the beryl crystal is highly unlikely.
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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"
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 :)
 
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So you are trying to move those SiF4 molecules through the channels that are only barely large enough for water?
 


chemisttree said:
So you are trying to move those SiF4 molecules through the channels that are only barely large enough for water?

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
 


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.
 


chemisttree said:
Do you have any information that HF can preferentially strip silica from the crystal of beryl without utterly destroying it?

Is this even possible theoretically?
 


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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