Vol. 7, No. 11, November 1968
EXCHANGE RATESFOR GROUPV PENTAHALIDE MOLECULES2229
We found that the net reaction of an excess of neptunium hexafluoride with sodium fluoride a t 250’ stopped with the formation of the 3: 1 compound in the presence of an overpressure of about 146 torr of neptunium hexafluoride and 10 torr of fluorine. Therefore, the ratio of P N ~ F ~ / $ Jin F ~the ” ~ gas phase over 3NaF.NpF5 necessary to initiate formation of the 1:1 compound, as expressed by eq 5 , is greater than IomIrich, and S. R. Piprce, J . A m . Chum. .Sot., 89,2017 (1967). (14) C. C. Costain and G. B. B. 11. Sutherland, J . Phys. Chent., 56, 32 (1952), and references cited therein. (15) R. I
