Isotope separation process

DETAILED DESCRIPTION The uranyl compounds including at least two isotopes of the element which is to be separated (for example uranium or oxygen) and having an isotopically shifted infrared absorption spectrum associated with the uranyl ions containing that element which are employed in connection with this invention have the general formula (UO.
sub.
2 AA').
sub.
n where A and A' are monovalent anions and n is an integer greater than 1, i.
e.
from 2 to 4.
Where n is 2, 3 or 4, the dimer, trimer and tetramer, respectively are produced.
Preferably, both A and A' will comprise the same anion, so that the general formula for the compounds useful in the process of this invention will be (UO.
sub.
2 A.
sub.
2).
sub.
n.
In a preferred embodiment thereof A comprises 1,1,1,5,5,5-hexafluoroacetylacetonate (hfacac).
The anions A and A' utilized in the uranyl ion-containing compounds utilized in the process of this invention are preferably selected so as to enhance the Lewis acidity of the complexed uranyl ion.
For this reason it is found, for example, that more fluorinated species of anions generally tend to be more preferred for use therein.
It is also preferred that these anions themselves have a minimum volatility, i.
e.
, such that they will boil, at pressures of about 1 atmosphere at temperatures of below about 200.
degree.
C.
As is set forth in pending U.
S.
Application Ser.
No.
961,363, filed on Nov.
16, 1978, the anions A and A' for use in these compounds of this process, when polydentate, thus forming a chelation ring around a part of their respective uranyl ions, must be such that these chelation rings will not open and bridge at the elevated temperatures at which these compounds are intended to be used.
If these rings were to open and bridge with adjacent uranyl ions at lower temperature, there would at the very least be a severe reduction in their volatility.
It is therefore preferred that these anions, A and A', have an atomic framework with a minimum length corresponding to that of the diketonate unit, so as to form relatively unstrained chelate rings