11 
On analysis it yielded, as the mean of four determinations 
made on different preparations, 
Cl 21-06 
Cr 48-91 
numbers approximating to those obtained by Hr. Zettnow. 
To this compound I was induced, for reasons which I need 
not here reproduce, to give the formula 
ClCr0 2 . 0. CrO. Cr.0 2 Cl. 
and to regard it as the chromium term of a series of salts a 
few members of which had already been described by 
Peligot, viz. — 
Potassium chloro-chromate 
CICrO.,. 0. K, 0. CrOoCl 
Sodium 
do. 
CICrO.,. 0. Na 2 . 0. CrOX’l 
Ammonium 
do. 
— CICrO.,. 0. (NH 4 ) 4 . 0. CrO.,Cl 
Magnesium 
do. 
CICrO.,. 0. Mg. 0. CrO.,Cl 
Calcium 
do. 
CICrO... 0. Ca. 0. Cr0 2 Cl, 
The above formula for the chromium chloro-chromate 
requires 
Cl 21-86 
Cr 48-54 
From the close agreement in the analytical results and 
correspondence in their physical properties, I am inclined to 
believe that Hr. Zettnow’s compound is identical with mine. 
Potassium chloro-chromate heated with sulphuric acid yields, 
among other products, chromyl dichloride, and, doubtless 
Hr. Zettnow’s compound has been derived from this body 
under circumstances analogous to those in which I have 
already operated. As my little notice on this matter has 
evidently not come under Hr. Zettnow’s observation, he 
may be interested to learn that the six or seven weeks’ 
time which he finds necessary to give to the preparation of 
this rather uninteresting compound may be considerably 
shortened by simply heating the chromyl dichloride in a 
closed vessel, when in a few minutes any wished-for quantity 
may be transformed almost completely into the chromium 
chloro-chromate and free chlorine. 
