146 



MR J. Y. BUCHANAN ON THE 



ClU., 



Hexagons of the Type m [M]. 



CIO, CIO, 



Br 



BrO, 



BrO, 



Br / "" T 



1/256 



Br 



^^ 1/512' ^ 



Br03 CIO, 



K 



Br0„ 



CIO, 



IO3 



BrO, 



10, 



CIO, 



10, 



Br 



1/128 

 Rb 



BrOg 

 1 



10, / , \ 010, Br 



^ 1 /256 ^ 



CI 



1/512 

 Rb 



CIO, 



CI 

 10, 



I03 



10, 



1/64 

 Cs 



^^rOg ^1/128' ^^*^« ^^'0" ^-^-^ t 



CIO3 Br 



Cs 



BrOg/^^gJ^ CIO" 



ClOg Bi 



Cs 



CI 



01 



The outstanding feature of the m [M] hexagons is the position occupied by IO.3, which 

 corresponds to CsOg in the m [R] hexagons. Whereas CsOg in these solutions occupies 

 place 6 in eight out of twelve solutions, IO3 does not occupy place 6 in any of the m [M] 

 solutions. In two cases it occupies place 1, in one case place 2, and in six cases 

 place 3 ; thus, in nine cases out of twelve it is found in the first three places of the 

 hexagon, and in the three remaining cases it occupies place 4. It is most frequently 

 found at place 3, which in the regular system is the place for I. But I is never found 

 elsewhere than in places 5 and 6. It occupies place 6 eight times, and place 5 four 

 times. Therefore, the feature of the m [M] hexagons is that I and IO3 have exchanged 

 their regular places. Indeed, if we change them back again in the m [K] solutions for 

 which m=l/64 and 1/128, we get the regular arrangement corresponding to that of 

 1/64 [CI], namely, CI, Br, I, CIO3, BrOg, IO3. This preference of IO3 for the final 

 place in the first triad, in place of I, which takes that in the second triad, is quite 

 comparable with the interchange of functions between K and KO3 as regards the 

 initial positions in the triads of salts of nucleus R. 



The other four residues confine themselves very closely to their own triads ; thus 

 CI does not leave it at all ; Br leaves it only once ; CIO3 also leaves it once, and 

 BrOg three times. 



