ABSTRACTS 



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PHYSICAL CHEMISTRY.— r/7^ color of inorganic compounds. F. 

 Russell v. Bichowsky. Joum. Amer. Chem. Soc. 40: 500-508. 

 March, 191 8. 



It is shown that every valence state of an element can be associated 

 by means of purely experimental evidence with a definite "atom color." 

 There is a marked relation between atom color thus determined and 

 valence and valence variability. The atom color of every element in 

 its normal valence state, that is, in the valence state which corresponds 

 to its place in the periodic system, is zero (all nonvariant-valence 

 atoms have their normal valence). The atom color of an element, in 

 valence states where the valence is decreased or increased by an odd 

 number from the normal valence, lies further in the blue than the atom 

 color of the same element in any other valence state. The atom color 

 of an element in a state whose valence is removed by an even number 

 from normal will be zero if compounds of the element do not exist in 

 which the valence of the element is removed by an odd number from 

 normal; otherwise the atom color will lie ftu-ther in the yellow than 

 the atom color of the same element in a state of valence removed by 

 an odd number from normal. Compounds between nonvariant- 

 valence elements will be colorless. Compounds between a nonvariant- 

 valence element and a variant-valence element will have the same color 

 as the "atom" of variant-valence element. Compounds between other 

 elements will have colors more to the blue than the sum of their atom 

 olors. All these regularities can be deduced from a variation of Lewis's 

 theory of atom structure. The almost perfect accord between the de- 

 duction and the facts indicates very strongly that Lewis's fundamental 

 hypotheses are correct. F. R. B. 



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