The zero-ppm signals E are plausibly solvated lithium halide, predominantly LiBr or LiI and their solution ion-pair/aggregate forms. Structural symmetry predicts one Li environment in A, two in B in a ratio, two in C in a ratio, and one in an ideal symmetric D.
The natural lithium assignment is therefore:
- Br mixture: A at approximately (43.4); B at approximately (16.2, three Li) and (5.4, one Li); D at (10.3, broad); E at (24.8).
- I mixture: A at approximately (59.9); B at approximately (8.4, three Li) and (2.8, one Li); C at approximately and (0.6 each); D at (2.3, broad); E at (3.0). The close C/D signals require care about overlap.
The major proton peak near is A. The next peak near to is naturally assigned to B; in the iodide mixture the smaller peaks near and distinguish C and D. Smaller D aggregates can exchange Li or ligands with free halide-containing species more rapidly, giving intermediate-exchange broadening at the two specifically identified broad lithium resonances.
There is a quantitative inconsistency in the printed integrations under these ideal single-species assignments. For example the Br lithium B integrals give molecular amount proportional to , while A gives . Their proton areas should consequently obey , whereas either small proton integral gives . No common proton-versus-lithium calibration removes that ratio discrepancy. Similarly the I B/A ratio predicted from Li is , compared with printed .
Thus the symmetry-based assignment above is useful, but an exact simultaneous quantitative assignment satisfying every printed reliable integral is not established by these data. It would require corrected integrals, an explicitly overlapped signal or an additional speciation model; the discrepancy should not be concealed by treating independently normalized spectra as automatically consistent.