166 Dr. E. TranMand on Organo-boron Compounds. [June 15, 



density, on the assumption that, in passing from the liquid to the gaseous 

 condition, the compound is broken up into its two constituent molecules — 

 boric ethodiethylate and boric ethylate. On volatilization, therefore, it 

 behaves exactly like ammonia boric methide (NHg, BMeg) described in 

 my former paper; and this deportment suggests the possibility of a 

 pentadic condition of the boron atom corresponding to that of nitrogen, 

 phosphorus, and arsenic. On this supposition the compounds just 

 mentioned would have the following constitutional formulae : — 



H Me 



Ammonia boric methide H — — M^e 



i Me 

 Et Et 



I I 



Diboric ethopentethylate Et — B = B — — Et 



Et Et 



Brought into contact with water, diboric ethopentethjdate is instantly 

 decomposed, forming boric acid and boric ethodihydrate : — 

 BEtEto^BEtOg + 50H, = BEtHo, + BH03 + SEtHo. 



Diboric ethopentethylate. Water. Boric ethodihydrate. Boric acid. Alcohol. 



If the quantity of water used for this decomposition be small, the boric 

 acid separates, almost completely, in minute crystals, whilst the boric 

 ethodihydrate remains in solution, and may be obtained in the crystalline 

 form by simple evaporation over sulphuric acid in vacuo. 



Boric Diethethylate. 

 Intermediate between boric ethide and boric ethodiethylate, theory 

 indicates the existence of a compound containing an atom of boron com- 

 bined with two semimolecules of ethyl and one of ethoxyl, 



BEt^Eto. 



I find that this body is produced in large quantity when boiling boric 

 ethylate is digested for several hours with twice as much zincethyl as 

 that which was employed to form diboric ethopentethylate : — 



BEtOg + 2ZnEt, = BEt.Eto + 2ZnEtEto. 



Boric ethylate. Zincethyl. Boric diethethylate. Zincic ethethylate. 



After rectification in an atmosphere of carbonic anhydride, the product 

 boiled at 102° to 104° C; but analysis showed that it persistently retained' 

 a small quantity of boric ethylate, or diboric ethopentethylate, from 

 which it could not be freed by repeated rectification. "When, however, 

 diboric ethopentethylate was treated with the necessary amount of zinc- 



