[budullewraagh]

the other day i was looking through my "lange's handbook of chemistry" and i stumbled upon a table that had many compounds and their solubilities in H2O at various temperatures. out of curiousity, i looked for the most soluble compounds. i found antimony trichloride and found that at 40 celcius, 1368g of it can dissolve in 100mL H2O. it said that at 72 celcius it is completely miscible.

does anybody here find it to be possible to continuously add SbCl3 to H2O and NEVER precipitate it? i'll throw around some figures:

121.760+3*35.45=228.119=1 mole SbCl3.
1368/228.119=5.996870055M=saturated solution of SbCl3 in 100mL H2O.
100/18=5.5555 (repeating).
there are more moles of SbCl3 than H2O at 40 celcius. therefore there are more molecules of SbCl3 than H2O at 40 celcius. the number of H2O molecules is only 92.64091942% of the number of SbCl3 molecules there are. the Sb+3 migrate towards the O end of H2O while 3 Cl- atoms migrate towards the H in H2O.

that makes sense, except the Sb+3 and Cl- are so close to one another when in this saturated aqueous solution that i don't see why they don't precipitate.

also i'd like to add that the above calculations are only for the 40 celcius reading; again, at 72 celcius SbCl3 is "completely miscible".

[movies]

I'm not sure about this, but my guess would be that the SbCl3 is more covalent than you think.  The Sb center is large enough to accept a lot of solvating water molecules.

I assume that SbCl3 is a liquid at 72 degrees, since miscibility is usually reserved for two liquids.

[budullewraagh]

pauling and allred-rochow say the electronegativity of Sb is 2.05 and 1.82 respectively whereas that of Cl2 is 3.16 and 2.83 respectively.  i suppose it is more covalent than i thought at first.

it sublimes at 100 celcius and fumes in air according to the merck index

[hmx9123]

For what it's worth, I used a fairly concentrated solution before, and it was more of a paste than anything.  Burned like hell when I got it on my fingers, too.