THE SULFIDES OF CARBON KENNETH A. KOBE,UNIVERSITY OF MINNESOTA, MINNEAPOLIS, MINNESOTA
The relationships of the periodic table are illustrated by the carbon compounds of oxygen and of sulfur. Carbon disulfide, carbon monosulfide, and carbon subsulfide are well-established componnds and other sulfides have been reported. The chemistry of these compounds is discussed with regard to the relation behneen oxygen and sulfur. That both elements can exist i n a compound is illustrated by carbon oxysulfide.
. . . . . .
The relationships of the periodic table are often illustrated by the formation and properties of analogous compounds of oxygen and sulfur, which show not only the close relationship of many componnds but also the tendency toward combination with the higher valences of the heavier element. The carbon compounds of oxygen and sulfur are not suitable for examples for no elementary text mentions any sulfide of carbon other than carbon disulfide or mentions that a mixed compound with both oxygen and sulfur exists. The existence of sulfides of carbon analogous to the oxides of carbon (1) is known and illustrates the relationships of the periodic table. Carbon Disulfide Carbon disulfide is commercially prepared in large quantities by the direct action of snlfnr vapor on carbon a t a temperature of 850' to 900° (2). An electric arc melts and vaporizes the sulfur which rises through a bed of charcoal or coke, forming carbon disulfide which passes off a t the top of the furnace and is condensed. The commercial product has a disagreeable odor due to the presence of other sulfur compounds. When purified (3), however, it has a sweet odor similar to chloroform. The sulfur analog of carbon dioxide should also be an acid anhydride and is the anhydride of thiocarbonic acid, H2CSa,in which sulfur atoms replace the oxygen atoms of carbonic acid. As early as 1826 Berzelius (4) showed that carbon disulfide dissolved in a solution of sodium sulfide to form sodium thiocarbonate which could be precipitated as a yellowbrown oil by the addition of alcohol. If he added dilute hydrochloric acid to the solution, free thiocarbonic acid separated as a yellow-red oil. Thiocarbonic acid is much more stable than carbonic acid, possibly since carbon dioxide is a gaseous product of decomposition. Percarbonates may be formed by the action of hydrogen peroxide on the alkali carbonates or by passing carbon dioxide into a solution of a peroxide. Na-O--(tNa
+ COX+O = C
