194 ANNUAL OF SCIENTIFIC DISCOVERY. 



ORGANO- METALLIC RADICALS. 



M. Cahours, in a recent number of the Annales de Chimie, publishes a most 

 elaborate article on the above-named substances, from which AVC notice a few 

 points of interest. The writer observes that there exists for simple bodies 

 capable of union a point of saturation which exhibits an equilibrium that 

 cannot be exceeded. So long as this state of equilibrium is not reached we 

 can add to the first substance a new proportion of the second, until saturation 

 is effected. Also, there are certain bodies which, when united to another, 

 give products whose combining power is more energetic than that of the 

 simple substance. Of these he enumerates oxide of carbon, sulphurous acid, 

 etc., which not only are able to absorb fresh quantities of oxygen with 

 greater facility than carbon and sulphur, but Avhich are able to form with 

 chlorine, iodine, etc., compounds corresponding to those of maximum oxy- 

 genization. These groups, which can be separated intact from their combi- 

 nations, and which subsequently pi'esent all the appearances of simple bodies, 

 are named radicals. Every compound may be regarded as a system of mole- 

 cules in equilibrium, whose atoms are attracted by affinities more or less 

 strong. If we replace one or several of these atoms by an equal number of 

 some other substance, we obtain new compounds, which present the same 

 mechanical grouping as the primitive product, and whose equilibrium will 

 vary within any extended limits, according to the force of the attractions of 

 the elements of the new substance. Thus ammonia can exchange all or part 

 of its hydrogen for chlorine, bromine, iodine, carbon, erhyle, metals, etc., to 

 form compounds belonging to the same system, but in variable states of 

 equiibrium. Thus, while ammonia resists a dull red heat, chloride of nitrogen 

 is destroyed at a temperature below that of boiling water. When methyle, 

 eihyle, amyle, etc., unite with certain simple bodies, they engender products 

 whose affinity for oxygen exceeds that of the simple substance. Thus zinc, 

 whose behavior to Avater at ordinary temperatures is very quiet, decomposes 

 it with violence when united with methyle or ethyle. The same occurs with 

 magnesium and aluminium, and still more so with the most electro-positive 

 metals, such as potassium and sodium. The most electro-negative metals, 

 such as zinc, tin, lead, and mercury, which, like the preceding, can couple 

 themselves with the alcoholic radicals, form, like them, compounds wuh a 

 strong affinity for oxygen, chlorine, etc. ; but these affinities are less ener- 

 getic, and when the saturation point is obtained, they comport themselves 

 as inert substances towards these bodies. The compounds of ethyle and 

 methyle with metals, being able to separate themselves intact from new 

 combinations, play the part of elementary substances. The curious proper- 

 ties of the metallic ethylides and methylides, which behave like real metals, 

 more electro-positive than the simple metals which they contain, have created 

 legitimate doubts as to the elementary character of the metals themselves. 

 Ethyle and methyle unite with the electro-negative bodies which stand at the 

 head of the series of simple bodies (oxygen, chlorine, etc.) and form stable 

 and neutral compounds. As we descend the scale and approach potassium, 

 which is at its base, we obtain less stable compounds invested with such 

 energetic affinities for the substances higher in the scale, that a molecule is 

 displaced, and simple and stable compounds produced. The remainder of 

 the paper is occupied with descriptions of metallic compounds of ethyle and 

 methyle. 



