NEPTUNIUM.205 SILVER

Seaborg s group placed a uranium nitrate sample in the path of the neutron-seeded cyclotron particle beam and made a sample. In the sample they found an element chemically different from all other known elements They had made plutonium, the name eventually given to the new element 94. (During the war they had to refer to both elements 93 and 94 in code, so neptunium became silver and plutonium became copper —as distinguished from honest-to-god copper. 0 The sample was stored in a cigar box donated by G. N. Lewis. 

The subsequent reaction between hypobromite and bromite has been shown to be rapid, requiring fast reaction techniques for its characterization. The oxidation of neptunium(vi) by hypobromite has been studied in alkaline media, stable neptunium(vn) salts being formed. There is a rate dependence on hydroxide ion concentration, and nickel(n), cobalt(n), or copper(n) ions increase the reaction rate whereas silver(i) or iron(ii) have no effect. 

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