In a message dated 2/19/99 9:10:56 PM Eastern Standard Time,
[log in to unmask] writes:
 
<<  SHELL CLEANING: Can anyone tell me what sulphate of chloride of magnesia
 is ? I came across it in an ancient shell-collecting book. It is
 supposed to make the animal swell up and go comatose if you put it into
 seawater with the shells. Then they don't coil up tightly inside so you
 can't get them out. If anybody knows it's common name, please let me
 know.
 >>
 
        I am posting this on list because it may be of interest to other people.
Since I am in the middle of chemistry classes, this question interested me a
great deal. I consulted my old chem professor who retired last year with the
question and he came up with this.
"
Many elements had the suffix "-ia" added to indicate the oxide.  Thus
magnesia is MgO.  The element below Mg on the chart is slightly unusual
because its oxide is not called calcia, but rather "lime".  Their
compounds were treated similarly however, with "milk of magnesia" and
"milk of lime" being the hydroxides.  Chloride of lime, or "bleaching
powder", is the mixed chloride/hypochlorite, CaCl(OCl).  By analogy,
chloride of magnesia should be MgCl(OCl).
 
The sulfate part is more problematic.  It might mean that sulfate (minus
2) is somehow substituted for the chloride (minus 1).  In that case, the
"compound" might be something like Mg2SO4(OCl)2 or MgSO4.MgCl(OCl).  (This
might be somewhat plausable.  That is, I seem to remember that the
sulfate of copper(II) was once used as an "anesthesia" for capturing
tropical salt water fish.)
 
OTOH, if you go back far enough (the 30's), diethyl ether was once called
"sulfuric ether".  I suspect that using ether as a solvent for chloride of
magnesia would do a good job of relaxing the poor snail.
 
Bottom line:  I don't know.
"
 
 
-Sarah