ORGAXOMETALLIC BODIEa 



OROANOMETALLIC 



compound* of these bodies with xinoetby 1, according to the following 



ZincstbTl. 



Zinccthyl. 



Double compound of wdiumrthj 1 

 and iincrthj-1. 



PotaMlumcthjl and zincclhyl. 



Sodium "also displaces mercury from mercuric cthido ; sodiumethyl 

 appear* to be formed, but the exact nature of the reaction has not been 

 ascertained. 



PROPERTIES or OIIGAXOMETALLIC BODIES. 



The organometallic compounds as a class are distinguished for the 

 extraordinary energy of their affinities. With certain exceptions, pre- 

 sently to be noticed, their disposition to unite with negative elements 

 increases with the positive character of the metal, and with the small- 

 ness of the atomic weight of the alcohol radical. Thus organo-potassium 

 and sodium compounds possess more chemical energy than those 

 of zinc, whilst the latter are more active than the organo-compounds 

 of arsenic, antimony, tin, lead, &c. Again, in the family belonging to 

 each metal, the methylic compounds are more energetic than the 

 cthylic ones, whilst the last greatly surpass the amyl compounds in 

 this respect. But whilst these general principles govern the chemical 

 energy of organometallic bodies, their effect appears to be modified by 

 the degree of saturation in which the metal exists. Although this 

 circumstance has hitherto received only very partial elucidation, yet we 

 have evidence of its existence in the case of the organo-tin compounds. 

 Both stannous ethide and stannous methide combine directly with 

 atmospheric oxygen, and the union takes place with tolerable rapidity, 

 but neither stannic ethide nor stannic methide are in the least degree 

 acted upon by free oxygen at ordinary temperatures ; even iodine acts 

 upon them with difficulty. This diminution of chemical energy in 

 organostannic compounds cannot be ascribed to the mere influence of 

 the additional weight of hydrocarbon which they contain, since stannous 

 amylide readily unites with free oxygen at ordinary temperatures, 

 although the single molecule of amyl which it contains is considerably 

 heavier than the double atom of either methyl or ethyl contained in 

 the organostannic compounds just cited. 



Organometallic compounds in a state of partial saturation play the 

 part of compound radicals. They are uniatomic, biatomic, teratomic, 

 or quadratomic, according to the number of molecules requisite to 

 complete their saturation. On the other hand, organometallic bodies 

 in a state of saturation never perform radical functions, they never 

 undergo chemical change without decomposition : thus zincethyl, 

 stannic ethide, mercuric ethide, and plumbic ethide all give substitu- 

 tion products when they are chemically acted upon. 



The description of the special properties of the organometallic bodies 

 may be conveniently commenced with the most positive of the class, 

 namely : 



Organo-jmtatilum and t odium compounds These bodies have not 

 yet been isolated, they are known only in combination with the corres- 

 ponding zinc compounds. The double compound of sodiumethyl and 

 zincethyl is the only one which has hitherto been submitted to 

 analysis. Its formula is 



: + *** 



This compound first separates from its solution in zincethyl as a 

 transparent fluid, which, after some time, solidifies to a mass of large 

 tubular crystals, which fuse at 27 C., but when once fused, 

 fluid at several degrees below that point. On the application of a 

 moderate beat, gases are evolved, and a mixture of sodium and zinc 

 without carbon is left behind. The double compound decomposes 

 water with great violence, forming hydride of ethyl and bydrated 

 oxides of zinc and sodium. The behaviour with negative elements has 

 not yet been studied. Its most interesting reaction consists iu the 

 absorption of carbonic acid, which it transforms into propionic acid. 

 The sodiumethyl alone takes part in this reaction. 



NaC.H, H 

 SouiuDutliyl. 



C,0 4 



Propionntc of nodi. 



Similar double compounds, containing t'dinmmtlltyl, as well as the 

 potassium compounds of ethyl and methyl, have been formed. They 

 have not yet been completely investigated, but it is brli. \.<1 Hint 

 tlirir ci>tii|Mxiti<>n and jnojierties are perfectly analogous to those of 

 Hodiumetliyl. 



N . compound of any of these bodies with a negative element has 

 been obtained. Their action upon carbonic acid proves that they 

 possess a still higher reducing power than the corresponding organo- 

 zmc compounds, and they will therefore doubtless prove valuable 



agents for the substitution of positive groups for negative elements in 

 cases where organo-zinc compounds fail to produce the desired effect. 



Sodiumethyl decomposes the iodides of the alcohol radicals iu the 

 cold, with the formation of iodide of sodium. 



K.C.H 



cthjl. 



Il\ hide of 

 ethyl. 



On this account, these bodies can only be prepared by method No 4. 



Organo-maynaium comjMundt. The compounds containing ethyl 

 and methyl only have hitherto been examined, and the former alone, 

 submitted to analysis. These bodies possess a close similarity to 

 organo-zinc compounds. They are very volatile colourless liquids 

 possessing a powerful alliaceous odour, are spontaneously inflammable, 

 and decompose water with violence. They do not readily decompose 

 the iodides of the alcohol radicals, and can hence be prepand by tho 

 method No. 1. No compound of these bodies with negative el. 

 has yet been produced. They are in the condition of chemical satura- 

 tion. Further details of their properties are wanting. 



Organo-alttmiiiiiim mmpiiunrit. Like the organo-compounda of tho 

 alkaline metals, the aluminium compounds have not yet with certainty 

 been isolated; they are only known in combination with io. 

 aluminium, and the composition of the ethyl body only has been fixed 

 by analysis. Its formula is 



A: 



C 4 H, 



+ Al, 



These double compounds possess great chemical energy; they ore 

 spontaneously inflammable volatile liquids, which decompose water 

 with explosive violence. They are attacked by zincethyl, forming 

 iodide of zinc and very inflammable liquids, which are believed to be 

 the pure organo-aluminium compounds. They appear to be chemically 

 saturated bodies, and therefore incapable of direct combination. Further 

 details are wanting. 



Organo-glucinum compound. The metal glucinum acts upon iodide 

 ethyl, forming a liquid which rapidly decomposes water, and which is 

 believed to be analogous to the double iodethide of aluminium above 

 described, but it has not been further examined. 



Orijano-zinc compound*. Three of these are more or less completely 

 known, namely : 



Zincmethyl 



Zincethyl 



Zincomyl 



Zn > { c|iit 

 '^{C^H" 



They are colourless, transparent, mobile, volatile, and odorous 

 liquids, composed of 4 gaseous volumes of the hydrocarbon radical, 

 and 2 volumes of zinc vapour, the six volumes condensed to 4. Tho 

 methyl and ethyl compounds are spontaneously inflammable, burning 

 with a greenish-blue flame. All three are saturated compounds, in- 

 capable of direct combination. In contact with water they are instantly 

 decomposed with the formation of oxide of zinc, and hydride of the 

 organic radical. Thus zincethyl sufl'ers the following decomposition : 



Zincethyl. 



Hydride of ethyl. 



Gradually treated with oxygen, so as to avoid too violent action, they 

 form the respective zinc alcohols : 



Xiiiocthyl. 



Jithyliitc of zinc. 



The action of iodine upon organo-zinc compounds consists in tho 

 transformation of both their constituents into iodides : 



Zn- 



Xinccthjrl. 



Iodide of ethyl. 



Organo-zlnc compounds behave in a manner exactly analogous in 

 contact with tho otbsr halogens. 



ii..n-, lil." tli.' i'..iv n ', inx point to tho applicability of organo-zinc 

 compounds for effecting the substitution of positive groups fur negative 

 elements in compound bodies; an application whixvh has not fai 

 attract tho notice of chemists. In addition to re-actions of this class, 

 given above, as examples of the formation of organometallic bodies by 

 the third method, the following have been realised : 



