279 



Angles : 



Observed: Calculated-. 

 (Jaeger) : (Zambonini) : 

 53° 59' 



m:b =(110): (010)=* 53°54' 



m:.) =(I10):(in)=* 45 33 45 30 — 



b-.iJi =(OTO):(lTO)=* 32 40 32 37 — 



c:,u. = (OOT) : (1 10) =* 94 40 94 38 — 



c:m =(001): (110)=* 76 40 — — 



m : // = (1 10) : (1 ÏÖ) = 93 20 93 24 93026' 



;/:w =(lT0):(lllT= 96 25 96 18 96 30 '/a 



c:f = (OOT): (112)= 43 42 — 43 59 



m:o =(110):(111)= 34 38 — 34 20 



c:o =(001):(111)= 42 20 — 42 20 



C:o> = (OOT) : (llF) = 57 46 56(?)46 57 46 



m:| =(110):(Tl2)= 78 13 — 77 59 



.iU = (111): (112)= 70 17 70 16 70 13 



y.:| =(irO):(Tl2)= 50 58 50 51 5145 



a : ,« = (100) : (iTO) = — — 34 47 



a: m = (100): (110)= — — 58 39 



No distinct cleavability was found. 



On all faces oblique extinction. The crystals are strongly dichroitic: 

 on in yellow and orange, quite analogous to the corresponding 

 ?V«Of//?^m-com pound. 



There can be no doubt about the complete isomorphism of the 

 crystals in this case with those of the /^Ao-salt. The corresponding 

 Co-salt was investigated by Copaux; it is also triclinic-pinacoidal, but 

 not isomorphous with the two other salts, probably because of a 

 difference in its content of water of crystallisation. Attempts will 

 be made to obtain the analogous cobalti-sedt. 



Afterwards we will communicate in detail about our fission- 

 experiments of potassium-rhodium-maJonate and oï potassium-iridium- 

 oxalate, as soon as their optical antipodes will have been obtained. 



Laboratory for Inorganic and Physical Chemistry 

 of the University, Groningen, HoUand. 



