40 

 (HOOG . CHJ, : C— C\ ^ /O— C : (CH, . COOH), 



I ^"b^^ I 



O = C— O-^^^O— = 



and 



O O 



0>^<0 



7,Zn 



In tlie cis 1.2 tetraliydro naphthalene diol and the cis 1.2 hydriii- 

 dene diol (both increasers of conductivity) the formation of an oil 

 can also be observed in siipersatnrated solution by addition of boric 

 acid. Aniline dissolves in these solutions, but a salt does not crys- 

 tallize out. 



I will state here liiat a furtiier proof of the constitution ot 

 these boron compounds can be furnished, if experiments to split 

 one of the asymmetric derivatives e.g. boron dicitric acid or nitro 

 pyro catechin derivatives into optical antipodes, should be successful. 



It is, therefore, probable, that we shall have to see the derivates 



of an unknown acid 



"HO . J, • OH 

 HO . . OH 



H in the more strongly acid 



boron complexes. The material described here may possibly be able 

 to throw some light on the so far obscure constitution of the boron 

 acids. As a working hypothesis we will now assume what follows: 



1. Maintaining the coordination value four for boron, the formula 

 for meta-boric acid becomes: 



[0:B:0]H. 



2. The mono-basic ortho boric acid is considered as meta-boric 

 acid being hydraled one-sidedly : 



™>B:0]h 



which can, however, pass into (is in ecpiilibrium with) the genuine 

 trihydroxyl boron B(0H)3, from which the well-known esters B(0R)3 

 have been derived. The first form is present to a certain percentage 

 particularly in aqueous solution, the second form especially in organic 

 solvents such as alcohol. The volatility of boric acid' might be 

 ascribed to the presence of B(OHj,. 



3. We start from the principle that a hydroxyl group bound (o 

 boron forms exceedingly easily an esterlike compound with alcohols. 



