19 
Pdligot has described a series of salts to which are assigned 
the general formulae M Cl, Cr0 3 and M"C1 2 , 2Cr0 3 , where M 
represents a monovalent metal and M" a divalent metal. 
The following are the names and formulae of the salts pre- 
pared by Peligot : 
K Cl, Cr0 3 Potassium chlorochromate. 
Na Cl, Cr0 3 Sodium chlorochromate. 
NH 4 C1, Cr0 3 Ammonium chlorochromate. 
Mg Cl 2 , 2CrO s Magnesium chlorochromate. 
Ca Cl 2 , 2Cr0 3 Calcium chlorochromate. 
Now the new oxychloride stands in a very evident rela- 
tion to these compounds. Supposing fora moment that the 
formulae given to these substances correctly represent their 
constitution, then the new oxychloride may be regarded as 
the chromium term of the series— -divalent chromium re- 
placing magnesium or calcium, 
Cr"Cl 2 , 2Cr0 3 , 
a formula identical with that of which I have just attempted 
to show the impropriety. But there is still another reason 
for supposing that a compound thus constituted could not 
exist. Chromous chloride is one of the most energetic 
deoxidising agents known, and we can hardly conceive it to 
be united in a stable compound with a substance which so 
readily parts with its oxygen as chromium trioxide. Hence 
I am disposed to regard the constitution of th e salts of Peli- 
got as very different from that implied by the above method 
of representation : indeed to the best of my knowledge the 
general formula assigned to these salts expresses not a single 
experimental fact, unless it be the mode of their decomposi- 
tion by water ; probably it had reference to the views of 
Rose and Berzelius respecting the constitution of the so- 
called chlorochromic acid. The following structural formulae 
better represent in my opinion the constitution of these 
compounds and their relation to chromyl dichloride* 
