CHEMISTRY. 383 



CHEMISTRY. 



Noyes, Arthur A., California Institute of Technology, Pasadena, CaUfornia. 

 Researches upon (1) the properties of solutions in relation to the ionic 

 theory, and (k) the determination of the atomic structure of crystalline sub- 

 stances by X-rays. (For previous reports see Year Books Nos. 2-19.) 



During the past year there have been prepared for publication the 

 extended researches carried out during the war period with the co- 

 operation of R. E. Wilson, R. C. Dickinson, and L. R. Westbrook on 

 the dissociation-pressure of salt hydrates. These researches, which 

 have now been published in the Journal of the American Chemical 

 Society, resulted in the development of two new methods of measuring 

 dissociation-pressure, and in determinations, more accurate than most 

 of those previously published, of the values for some typical hydrates. 



The researches on the properties of solutions in relation to the ionic 

 theory have been continued. The state in which bismuth exists in 

 solutions of its nitrate and perchlorate has been studied by Mr. D. F. 

 Smith with the aid of measurements of electrical conductance and 

 electromotive force. The results indicate that the salts mainly 

 present in moderately dilute solutions are of the type Bi(OH)(N03)2- 

 The electrode-potential of metallic antimony against solutions of an- 

 timonous chloride in hydrochloric acid has also been determined by 

 electromotive-force measurements and found to be about —0.20 volt 

 at 25° against a solution 1 molal in antimony, in hydrogen-ion, and in 

 chloride, this value signifying that under these conditions the antimony 

 is less reducing than the molal hydrogen electrode by 0.20 volt. 



The investigations on the determination of crystal structure by 

 X-rays have been continued by Mr. R. M. Bozorth and INIr. R. M. 

 Badger, with the close cooperation of Dr. R. G. Dickinson, who as 

 National Research Fellow is pursuing researches in this field in the 

 laboratory. The work accomplished during the past year has been 

 mainly as follows: 



An article on the crystal structure of sodium chlorate and bromate 

 (NaClOs and NaBrOs) has been prepared by Dr. Dickinson and pub- 

 lished in the Journal of the American Chemical Society. The sodium 

 and chlorine atoms were located with considerable certainty, and 

 the three oxygen atoms with a fair degree of probability. Dr. Dickin- 

 son has also successfully determined the structure of potassium 

 chlorostannate (K2SnCl6) and other similarly constituted compounds. 

 These compounds, in spite of their molecular complexity, belong to 

 the cubic crystal system; and the X-ray work has shown that the 

 group SnCle, which in solution exists as a separate molecule (carrying 

 two free negative electrons), maintains also in crystals its identity 

 to the extent that the six chlorine atoms are located much closer 

 to the tin atom than to the potassium atoms. 



