288 W. Gibbs on the Hexatomic compounds of Cobalt. 
eribed. Potassic iodide gives, with a solution of sulphate of 
Stebel brown yellow needles, which, after re-solution, 
gave larger prismatic crystals. Of these 
0°5396 gr. gave 0°2207 gr. SO,Co=15'57 per cent cobalt. 
0°8856 gr. gave 0°2689 gr. SO, ;Ba=12°51 per cent 
0°4541 gr. gave 0°1288 gr. silver =33°37 per cent iodine. 
The formula Co,(NH,), ,(NO,),SO,I, +20H, requires 
Cobalt, 2 15°40 15°57 
Iodine, 2 33°16 33°37 
60. 2 12°58 12°51 
When a solution of iodine in potassic iodide is added to one 
of sulphate of xanthocobalt, very itech ibe ruby-red, 
well defined crystals are formed, which are rea ily decomposed 
by hot water, with evolution of iodine vaeae and cannot be 
recrystallized for analysis. Of these crystals 
0°6094 gr. gave 86°5 c.c. ee at 13° C. ~~ habe *6 mm, (h= 
2°08 mm.)==16°63 per cent nitro 
0° "2142 gr. gave 0687 gr. SO,Co=12 ‘21 ce pets cobalt. 
The formula Co oh ii (NO,),80,1 , requires 
Calculated. 
Found. 
s 2 
Cobalt, 2 11°99 12°21 11°64 
Iodine, 4 51°60 49°90 49°96 
SO, n 9°75 9°77 10°80 
Nitrogen, 12 17-07 16°63 
Salts 1 and 2 were from different preparatio 
The analyses do not correspond as slau to the formula as 
might be wished, but it must be remembered that the salt can- 
not be recrystallized without decomposition, and is probably 
not quite free from the first described, or normal iodo-sulphate. 
The salt gives off iodine on heating. The structural formulas 
of the two salts may be written as follows 
(BES -NO, ‘NH, -NO, 
NH “NH, <2] NH, —NH,—-T. 
Coa} NHS ANI >SO, Cog: } NHOONIE =O>8<O21 
NH, —NH,-I NH.—NH.-I 
NH, —NO | NH,—NO, 
This mode —— sites the formulas, however, involves certain 
theoretical eondlubions, which I shall examine in detail here 
