Chemistry and Physics. 391 



SCIENTIFIC INTELLIGENCE. 



I. Chemistry and Physics. 



1. Sulphur Hexa fluoride, Thionyl Fluoride, and Sidphuryl 

 Fluoride. — Moissa^ and Lebeau have recently described several 

 new gases containing sulphur and fluorine. Sulphur hexafluoride, 

 SF 6 , is produced when gaseous fluorine is brought into contact 

 with sulphur. The sulphur immediately takes fire and burns 

 with a bright flame. The gas thus produced is very remarkable 

 for its great stability, as it has neither taste nor odor, and is 

 not decomposed by water nor even by caustic potash solution. 

 Although very rich in fluorine, the colorless gas, in its inertness, 

 resembles nitrogen rather than the chlorides of sulphur. It is 

 slightly soluble in water. At —55° it solidifies to a white crys- 

 talline mass which melts and then boils at a temperature a little 

 above its point of solidification. It is not attacked by fused lead 

 chromate, fused caustic potash nor by copper oxide at a low red 

 heat. Sodium may be fused in contact with the gas without 

 action taking place, but when the sodium is brought to the boil- 

 ing point combination takes place with incandescence. 



Thionyl fluoride, SOF 2 , is prepared by the action of fluorine 

 upon thionyl chloride, and also by the reaction of arsenious 

 fluoride with thionyl chloride. It is a colorless gas which fumes 

 slightly in moist air, and which has a disagreeable, sufibcating 

 odor. It is decomposed by water at the ordinary temperature, 

 with the formation of sulphur dioxide and hydrofluoric acid. In 

 general it is much more active than sulphur hexafluoride. 



Sulphuryl fluoride, S0 2 F 2 , is most conveniently prepared by 

 the combination of fluorine and sulphur dioxide. These gases 

 burn when brought together if the combustion is started by 

 means of a hot platinum wire. This is a remarkably stable gas, 

 but it is not quite as inactive as SF 6 . It is colorless and odor- 

 less, does not act upon water even at 150°, but is decomposed by 

 aqueous or alcoholic caustic potash with the formation of potas- 

 sium fluoride and sulphate. It becomes liquid at —52°, solidifies 

 when exposed to the temperature of liquid oxygen, and melts at 

 — 120°. It reacts with many substances at high temperatures. — 

 G. JR., cxxx, 865, 1436 ; cxxii, 374. h. l. w. 



2. The Molecular Weight of Ozone. — The molecule 3 is gen- 

 erally admitted to belong to ozone, but the facts upon which this 

 assumption is based possibly leave some room for doubt in regard 

 to the matter. A. Ladenbukg, therefore, has devised a new 

 method for determining the specific gravity of this gas. He 

 weighed a glass globe filled with dry oxygen, then filled it with 

 some of the same sample of oxygen after it had been ozonized 

 and weighed again at the same temperature and pressure. After 

 this he absorbed the ozone by means of oil of turpentine, and 



