CHEMICAL PROPERTIES 



Table 1-1 (continued) 



Compound 



Structure 



Distance (A) 



Cyclobutane-dicar boxy late 



Cyclopentane-dicar boxy late 



COO 



coo 



COO' 



Cyclohexane-dicarboxylate 



COO' 

 COO' 



COO 



^-Phosphonopropionate < 



(a) 



(b) 



'OOC-CHj 



"OOC 



CH,— PO; 



po: 



\ / 



CH2 CH2 



3.39 



3.72 



4.05 

 5.09 

 3.14 



The distances were calculated on the basis of bond lengths and angles given In Tables 1-6-12 and 1-6-13 

 except where direct measurements were available. It was assumed that the center of negative charge lies 

 midway between the resonating oxygen atoms. For o-phthalate and cyclohexane-dicarboxylate a 3° distortion 

 of the bond angles due to electrostatic repulsion was assumed. For cyclopentane-dicarboxylate a further 

 5° widening was estimated from the bending of the ring angles. The value for cyclobutane-dicarboxylate 

 is only approximate and is based on a 7° distortion of the bond angle in comparison to malonate. It should 

 be pointed out that the values in this table are smaller than generally used; one reason is that Intercarboxy- 

 late distances have usually been based on the distances between associating or dissociating protons , ra- 

 ther than between centers of negative charge. 



ionic strength. Since AH for the dissociation of weak acids is quite small, 

 the constants do not change much with temperature; d^K^JdT = 0.0031, 

 and d])Kg jdT = 0.0038, approximately. Three species will be present in 

 any solution of malonate — HOOC— CHg— COOH, HOOC— CHg— C00-, 

 and -OOC — CHg — COO" — the relative concentrations being determined 



