DE. A. W. HOFMANN ON THE PHOSPHOEUS-BASES. 
495 
According to Wetss: — 
«=0-6793 
Forms observed: — 
oo a : oo a : CO a : c; a: ^ a: a: coc; coa: a: a: c; co a' : a' : a' \ ^c; 
a\\a\a\\c\ a\\a \ a\ \ c. 
According to Levy : — 
PP = 83° 26'. 
Forms observed: — 
a', fZ, P, h\ h-, 
Fig. 48. 
Combinations observed : — 
3 IT; 10 0, 101 (Fig. 48). 
311, 111, 100 (Fig. 49). 
3 IT, 111, lOT; 100 (Fig. 50). 
3 IT, 110, 10 0; lOT, 210 (Figs. 51 and 52). 
3 IT, 10 0, 110; lOT, 210, 111. 
The crystals prepared by treating triethylphosphine with iodide of ethyl exhibit the 
forms Figs. 51 and 52. 
Fig. 51. Fig. 52. 
The crystals obtained by submitting the hydrated diphosphonium to the action of 
heat, and neutralizing the alkaline residuary product with hydriodic acid, have the form 
Fig. 48, when rather large and slightly yellow, and the forms Figs. 49 and 50, when 
minute and perfectly white. 
