cyanureeves
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what is this white stuff
i added ammonium hydroxide to tin chloride solution and right away got a white substance.what would be the name of that white compound? thank you.
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bfesser
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Hydrated <a href="http://en.wikipedia.org/wiki/Tin(II)_oxide" target="_blank">tin(II) oxide</a> <img src="../scipics/_wiki.png" />.
<a href="http://en.wikipedia.org/wiki/Tin(II)_hydroxide" target="_blank"> | Quote: | | There had been confusion as it had been believed that Sn(OH)<sub>2</sub> was precipitated when a tin(II) salt is reacted with an alkali
hydroxide such as NaOH, but this product was determined analytically to be hydrated tin(II) oxide, being either 5 SnO · 2
H<sub>2</sub>O or 3 SnO · H<sub>2</sub>O, The structure of pure Sn(OH)<sub>2</sub> is not known.
<img src="../scipics/_wiki.png" /> |
</a>
[Edited on 7/9/13 by bfesser]
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papaya
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Hydrated tin oxide/oxychlorides ?
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bfesser
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<strong>Papaya</strong>, I don't believe any oxychlorides are formed. What causes you to assert that they are?
[Edited on 7/8/13 by bfesser]
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papaya
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I don't state it, but if the SnCL2 is in excess to the base, what you expect then?
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bfesser
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So you have no evidence or reasoning, but you're telling him that tin(IV?) oxychloride is a product of the reaction? <em>Why are you even
posting‽</em>
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cyanureeves
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thank you gentlemen. i was googling for tinaminechloride.stannouschlorideammonia. so hydrated tin oxide it is and i must say it sounds better than
white stuff similar to "white stuff in south american cocaine manufacture video".i have been adding ammonia to copper salts all day almost just to
make blue stuff and man it is exciting when immediate stuff happens.
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Hexavalent
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He used a question mark, which means that he isn't sure, but it is a possibility. There is a difference between suggesting something for discussion,
which is perfectly valid, and stating something directly.
"Success is going from failure to failure without loss of enthusiasm." Winston Churchill
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papaya
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Quote: Originally posted by bfesser  | | So you have no evidence or reasoning, but you're telling him that tin(IV?) oxychloride is a product of the reaction? <em>Why are you even
posting‽</em> |
I never stated tin (IV) oxychloride as it must not change the oxidation state, rather I put a wrong name for Sn(OH)Cl, must be read
stannous hydroxy chloride I guess, which as stated on the wiki page you provided can form by SnCL2 hydrolysis. Note equilibrium, how it will shift
when you react HCL forming on right side with ammonia ?. This is why I "speculated" this way, I'm very sorry for that, of course I cannot find more
direct proof for that (that you'll never get a pure hydrate oxide), however even now this sounds very reasonable to me..
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bfesser
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<strong>Hexavalent</strong>, <strong>papaya</strong>; fair enough. My apologies for getting overexcited.
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papaya
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OK, but what do you think about my last post ? I mean Sn(OH)Cl formation, I'm in doubts now..
<!-- bfesser_edit_tag -->[<a href="u2u.php?action=send&username=bfesser">bfesser</a>: removed
unnecessary quoting]
[Edited on 7/8/13 by bfesser]
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bfesser
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http://en.wikipedia.org/wiki/Tin(II)_chloride#Chemical_properties
[Edited on 6/18/13 by bfesser]
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papaya
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Yes, but I see a mismatch there, because
first it says what I was thinking:
Tin(II) chloride can dissolve in less than its own mass of water without apparent decomposition, but as the solution is diluted hydrolysis occurs to
form an insoluble basic salt:
SnCl2 (aq) + H2O (l) is in equilibrium with Sn(OH)Cl (s) + HCl (aq)
Therefore if clear solutions of tin(II) chloride are to be used, it must be dissolved in hydrochloric acid (typically of the same or greater molarity
as the stannous chloride) to maintain the equilibrium towards the left-hand side (using Le Chatelier's principle).
but then it says:
If alkali is added to a solution of SnCl2, a white precipitate of hydrated tin(II) oxide forms initially; this then dissolves in excess base to form a
stannite salt such as sodium stannite
So at the end it doesn't say that with alkali addition you may end up partially with Sn(OH)Cl, why?
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bfesser
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I suggest we consult a source more reputable than Wikipedia. I'll <a
href="viewthread.php?tid=19098&goto=search&pid=288540">request</a> the paper cited in the article, as well as consulting my personal
library of books. This seems like something <strong>woelen</strong> may like to chime in on.
[Edited on 6/19/13 by bfesser]
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woelen
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I also think hydrated tin(II) oxide is a good option, but I'm quite sure that it will not be pure. Certainly, chloride ions are part of the
precipitate as well, but I do not think that you will get a precisely stoichiometrically determined compound like Sn(OH)Cl. I would say, Sn(OH)xCly,
with x + y = 2 and most likely x > 1, but at the latter I'm not 100% sure.
The problem with many kinds of precipitate reactions, especially with halides, is that non-stoichiometric compounds are formed. With colored ions one
can see the difference. A nice example is precipitating copper(II) with hydroxide from a chloride solution and from a sulfate solution. From the
former you get a greenish precipitate, from the latter you get a pure blue precipitate. The green precipitate contains a lot of chloride besides the
hydroxide and this has a strong influence on the color. With tin you can't see the difference, because all of these precipitates are white.
Another interesting thing: Hydrous tin(II) oxide is white, but the anhydrous oxide is dark grey. I have some of the anhydrous oxide and this easily
dissolves in hydrochloric acid and gives a colorless solution of tin(II) chloride.
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bfesser
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Thank you, <strong>woelen</strong>. Insightful as always!
By the way, the <a href="http://www.sciencemadness.org/talk/viewthread.php?tid=19098&page=19#pid288547">reference</a> has been posted
for anyone interested.
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