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The results of numerous determinations of 0.3-to 10mg quantities of potassium, rubidium, and cesium are summarized in Tables II, III, and IV. With quantities greater than 0.5 mg, the mean error (regard to sign) is -0.3% for potassium, -0.2% for rubidium, and -0.4% for cesium. There is no reason to suspect that these mean errors are small because of fortuitous compensation of errors in the precipitation and coulometric titration. On the contrary, since errors associated with the precipitation certainly will tend to be negative, such compensation would require positive errors in the coulometric titration, which seems very unlikely in view of the results of the assays of the commercial sodium tetraphenylborate (Table I). We conclude that if there is any significant systematic error in the coulometric titration it is not greater than about 0.4%, and very probably is smaller. In other words, the precipitation reaction between tetraphenylborate ion and silver ion is stoichiometrically exact.That potassium tetraphenylborate, wetted with water, decomposes on drying is demonstrated by the data in Table V. In these experiments, 25.00-and 50.00-mg samples of potassium ion were precipitated as described above. The washed precipitates were then dried either in an oven at 105°, oral room temperature in a vacuum desiccator, to constant weight. After weighing, the dried precipitates were dissolved in pure acetone to a known volume, and aliquots were then titrated coulometrically.The gravimetric results are uniformly too high by 1.0 to 1.5% and there is no significant difference in weight by the two drying techniques. In sharp contrast, the coulometric results (which measure the tetraphenylborate content of the dried precipitates) are consistently several per cent too low, and oven drying tends to produce a greater deficiency of tetraphenylborate ion than drying in a vacuum desiccator at room temperature. Presumably, the decomposition reaction is hydrolytic, and the fact that it produces an increase in weight indicates that the products are relatively nonvolatile.

A general procedure for synthesis of bicyclo[n.2.0]alkane-l,n-diols is described. The synthesis involves thermal cycloaddition of dichloroketene to a cyclic alkene to generate the bicyclic skeleton (e.g., 6), cine substitution with a carboxylate anion to give a bridgehead oxygen substituent (e.g., 12), removal of the remaining halogen with chromous chloride, and reduction to give diol (e.g., 14). The procedure allows for the synthesis of either cis or trans diols selectively.

Aus den Trialkylaluminiumverbindungen (I) entstehen mit Acetylen (II) die ungesättigten Vertreter (III), die mit Äthylenoxid (IV) über die Einschiebungsprodukte (V) zu den ungesättigten Carbinolen (VI) führen.

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