The literature contains only two references to a complex between an alkali metal hydride and a zinc compound. Wittig and Hornberger2 reported that a complex ZndCeHj^'LiH could be isolated as an etherate from the reaction between diphenylzinc and lithium hydride. Frey and co-workers8 mentioned a complex between sodium hydride and diethylzinc; however, no attempts to characterize the complex were made.Preparation of Sodium Hydride Complexes of Diethylzinc and Zinc Chloride.--We have found that sodium hydride will form an adduct with both diethylzinc and zinc chloride in glycol ethers. With monoglyme or diglyme as solvent, one mole of sodium hydride dissolved rapidly per two moles of diethylzinc to give a soluble product, but no additional sodium hydride would dissolve. Attempts to isolate the compound resulted in decomposition. The reaction would not take place in aliphatic or aromatic hydrocarbons, nor in diethyl ether or tetrahy dr of uran.
Anal.Gas composition on hydrolysis of NaH• 2Zn(C2H6)2: H2, 20; C2H", 80. Found: H2, 19.7; C2H6, 79.3.The corresponding adduct of sodium hydride and zinc chloride was prepared in solution by stirring 20 g. (0.15 mole) of zinc chloride and 4.0 g. (0.17 mole) of sodium hydride in glycol ethers. The solid reactants dissolved very slowly, requiring 2-24 hr. While the reaction was proceeding, in the presence of solid sodium hydride, two competing reactions apparently occurred, for precipitation of zinc metal and sodium chloride and some gas evolution were observed. These side reactions were more rapid in reactions run at elevated temperatures. The product solution after filtration contained active hydrogen as well as sodium, zinc, and chlorine, and apparently was stable at room temperature. After several weeks of storage, hydrolysis gave rapid gas evolution, indicating retention of hydride content.Attempts to isolate the solute by removing solvent under vacuum resulted in decomposition.Anal. Caled, ratios for NaH-2ZnCl2 in solution:Na/Zn/Cl/H = 1/2/4/1. Found: Na/Zn/Cl/H = 1.0/2.0/5.6/0.8. Ethylation of the Sodium Hydride Complexes.-A solution of NaH-2Zn(C2H6)2 in diglyme readily added (1) Presented in part before the Inorganic Division, 142nd National ACS Meeting, Atlantic City, N.
Bouguer-Beer law in textbooks of analytical or physical chemistry vary between two extremes. In simpler, more utilitarian texts, the law is taken as given, stated in either exponential or logarithmic form. This is probably quite satisfactory for ordinary purposes. The curious student is bound to be left a little perplexed (just why, at first glance, isn't the absorption of light a linear function of distance?). In more complete texts, the presentation based on calculus is usually given. The manipulations themselves are not difficult.Nevertheless, many students who have been exposed to calculus cannot use it in a very meaningful way, as we all know.The calculus-based presentation has in it some conceptual difficulties, and several articles have been written dealing with these.1'2 For example, there is the problem of combining the dependencies on concentration and length, when postulated separately. Beyond this, there is the idea of absorption occuring in an unimaginably thin layer of material, according to 1
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