41 



This enables the [fHO)jB : 0] H present in water to form compounds 

 with a number of glycols and a-oxy acids, of the following type: 



>C — Os 



,/ 



B:0 



H 



') 



>C— 



Like boric acid these acids are very weak. 



4. On the other side of the boron atom a compound can now be 

 formed with a second molecule of diol or oxy acid with loss of 

 water. Whether then a molecule of water is first admitted, may be 

 left undecided for the present. The existence of dipotassium salts, 

 to which we can assign the structure: 



>C— 0. /OH 



I ^B^ 



>C— 0^ \0K 



K 



may possibly plead in favour of this, like the presence of an extra 

 molecule of wafer in Dekx's solid mono cyclo heptane diol boric 

 acid and Fox and Gauge's mono mannite boric acid. 



A second molecule of dioxy compound is, however, received in 

 diluted aqueous solution in appreciable quantities only when certain 

 favourable conditions are realized, i.e. with a favourable steric situation 

 of the hydroxyl groups in the diol or oxy acid. The tendency to 

 the formation of a di-compound is, accordingly, smaller than that 

 to the formation of the mono-derivatives, and the former seems, 

 therefore, to be very sensitive to the value of the ring-tension in 

 the ring to be formed. This fact constitutes the hypothetical found- 

 ation of Bökskken's boric acid method. 



5. It is known that the poly-boric acids whose presence must 

 be assumed in alkaline solutions, are stronger acids than ortho-boric 

 acid. Plausible structure formulae could not be drawn up for this 

 large series of acids as yet on the basis of trivalent boron. Possibly 



they too possess the grouping n-^'^^n ' ^Jfl-i'if^'ning 'I'e as- 

 sumption that to each H-atom that can be replaced by metals belongs 

 one pentavalent B-atom, the other B-atoms being trivalent, a structure 

 schema may be constructed for a great number of poly boric acids. 

 Tetra borix acid, which forms the foundation of borax, possesses 

 e.g. the scheme : ') 



M In this connection it will be of importance to examine whether in the 

 saponification of B(OR):; by water tlie presence of a relatively stable intermediate 

 product (RObBOH can be shown. 



') This representation does not lay claim, of course, to be anything more than 

 a scheme. 



