Survey of the Actinide Element Halides

The actinide elements now constitute a fairly numerous group of compounds (Table I). An examination of Table I reveals a number of interesting 

Little need be said about the halides of actinium. All of the binary halides of this element have been prepared by conventional procedures, and the straightforward, uncomplicated chemical behavior that actinium exhibits generally is also evident here. Thorium, however, presents quite a different problem. Thorium gives no indication of existence in aqueous solution in an oxidation state lower than +4. From considerations of the 

The gaps in the list of protactinium halides are due not so much to the instability of the missing compounds but rather to difficulties in characterization. Until very recently, protactinium was the least studied of the actinide elements, primarily because of the great difficulties hitherto experienced in obtaining milligram amounts of pure protactinium-231. The lack of pure protactinium and the difficult chemistry of the element have made 

The (III) state is by far the most stable oxidation state for americium, and it is possible only by the use of fluorine to prepare a higher halide. Americium tetrafluoride has been prepared by direct fluorination, but attempts to prepare AmF5 or AmF have so far been fruitless. It is a reasonable presumption that AmF6 does not exist as a stable compound under ordinary conditions. 

Actinide Element Isotopes Suitable for Investigations with Macroscopic Quantities 

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