Prof. T. Carnelley on the Periodic Law. 

 Table III. — Illustrating Relations 3 and 4. 





Chlorides. 



Bromides. 



Iodides. 



an -g 



a ,a 



a> ft 



a .a 

 F* ° 

 '3 ^ 



la 



!*H O 



w 



1 .a .a 



-w o 



© ft 



w>a 

 a. 5 



B O 



•3 * 



«2 a 



+3 CO 



$ a 



(D ft 

 3 



It 



•3 * 



Heat of for- 

 mation. 







231 

 205 

 246 

 218 



326 

 254 

 409 



338 



351 

 331 

 408 

 339 

 495 

 389 

 556 



498 



39400 

 31700 



!! 364(?) 

 260 



312 



271 

 :367 

 303 



434 



372 



462 

 426 



503 

 428 



555 



474 



611 



555 



30100 

 28850 ! 



420 

 393 



423 

 399 



455 

 419 



515 



498 



620 

 563 



633 

 565 



681 

 568 



735 



659 



14000 

 20000 



Si 



Ti 



EkaSi ... 

 Zr 



Sn 



Oe 



EkaSn . . 

 EkaCe ... 

 Pb 





Relation 4. (a) For the chlorides, bromides, and iodides of 

 Groups ill. to VII., and of the even members of the second group, 

 the melting-point and boiling-point increase with the atomic 

 weight of the positive element. 



(b) For the odd members of the first and second groups, the 

 melting-point and heat of formation diminish as the atomic 

 weight of the positive element increases. 



(c) For the even members of the first group, the melting- 

 point and heat of formation increase from Li to K ? and then 

 diminish to Cs. 



For illustration see Table III. 



Relation 5. The differences between the boiling-points of the 

 chlorides and bromides, bromides and iodides, chlorides and 

 iodides are greater than those between the corresponding melting- 

 points. 



Thus:— 



Boiling-point. Melting-point. 



SnCl 4 389 254 



SnBr 4 474 J303 



Difference = 85 is greater thaii 49 



Sil 4 563 393 



SiBr 4 _42_6 Wd 



Difference = 137 is greater than 133 



See also Tables IV. and V. 



Relation 6. The differences referred to in Relation b, for 

 both melting- and boiling joints, increase algebraically from the 



