OF ARTS AKD SCIENCES. 231 



from manganons carbonate. The crystals freed from hygroscopic 

 moisture gave the following numbers : — 



52-38 



100.00 



Tlie salt was dissolved in water, the manganese precipitated with a 

 solution of sodic carbonate, and, after filtration, fluorine was thrown 

 down by calcic chloride. 



Properties. — Colorless, sometimes light pink. Crystals are trans- 

 parent long prisms of the trimetric system. Soluble in water, giving 

 acid reaction. Soluble in acids. Effloresces in air ; when heated at 

 lOO'^C, changes into the simple MnFg. 



Double Fluoride of Manganous Oxide and Potassium, MnF^. KF. 

 — On the addition of an excess of potassic fluoride to a solution of 

 manganous chloride, an immediate separation of an insoluble compound 

 results. A double decomposition ensues, which is expressed by the 

 reaction : — 



MnCl2 + 3KF = MnF2. KF + 2KC1. 



The precipitate collected on a filter is washed with water, then with 

 alcohol, and subsequently with ether. Alcohol and ether are employed 

 to remove the last traces of water, 

 same result : — 



Found. 



Mn 36-23 



K 26-06 



Fg 37-71 



100-00 100-00 



The method used in analysis was based upon the conversion of the 

 double fluoride into a mixture of sulphates of manganese and potas- 

 sium. The weight of the sulphates being known, as also that of the 

 manganese therein contained, the percentages of the metals were easily 

 calculated, while the fluorine was inferred by difl^erence. 



Properties. — Flesh colored. Crystalline. Insoluble in water and 

 alcohol. Not decomposed in air and water. Dissolves in acids. Fuses 

 at red heat. 



