Table 2.

NRT weights of the Lewis structures 1 and 2, and the associated non-Lewis RMSD errors in the NRT compared to using only a single resonance structure 1 or 2

	Weightsa		RMSDb
Compound	1	2	Only 1	Only 2	NRT
${{\left[\mathrm{UOU}\right]}^{2+}}^{\mathrm{c}}$	99	–	0.35	–	–
CUOd	75	26	0.28	0.44	0.07
${\left[{\left({\mathrm{R}}^{\mathrm{a}}\right)}_3{\mathrm{NTh}}^{\mathrm{IV}}\mathrm{N}\right]}^{2-}$	36	64	2.04	1.98	0.10
${\left({\mathrm{R}}^{\mathrm{a}}\right)}_3{\mathrm{NU}}^{\mathrm{VI}}\mathrm{N}$	45	55	1.84	1.84	0.09
${\left[{\left({\mathrm{R}}^{\mathrm{a}}\right)}_3{\mathrm{NU}}^{\mathrm{V}}\mathrm{N}\right]}^{1-}$	48	52	0.96	0.92	0.05
${\left[{\left({\mathrm{R}}^{\mathrm{a}}\right)}_3{\mathrm{NU}}^{\mathrm{V}}\mathrm{N}\right]}^{2-}$	34	66	1.29	1.25	0.06
${\left({\mathrm{R}}^{\mathrm{a}}\right)}_3{\mathrm{NU}}^{\mathrm{V}}\mathrm{O}$	60	40	0.88	0.92	0.05
${\left({\mathrm{R}}^{\mathrm{a}}\right)}_3{\mathrm{NNp}}^{\mathrm{V}}\mathrm{O}$	60	40	0.87	0.92	0.05
${\mathrm{MeU}}^{\mathrm{VI}}{\left({\mathrm{R}}^{\mathrm{b}}\right)}_3\mathrm{O}$	66	34	2.99	3.34	0.08
${\mathrm{PhCCU}}^{\mathrm{VI}}{\left({\mathrm{R}}^{\mathrm{b}}\right)}_3\mathrm{O}$	70	30	5.12	6.24	0.12
${\left({\mathrm{R}}^{\mathrm{a}}\right)}_3{\mathrm{NU}}^{\mathrm{VI}}{\mathrm{N}}^{\mathrm{e}}$	47	53	3.31	3.31	0.00

DFT/B3LYP calculations.

^aPercent weights of Lewis structures 1 and 2 of Figs. 1c and 1d in the resonance stabilized electronic structure according to NRT.

^bNon-Lewis RMSD (number of electrons).

^cThe dominant resonance structure for uranyl is O ≡ U ≡ O⁺².

^dThe resonance for CUO is [(1) C≣U ≡ O: ↔ (2):C ≡ U≣O].

^eData for the full experimental ${\left({\mathrm{R}}^{\mathrm{a}}\right)}_3{\mathrm{NU}}^{\mathrm{VI}}\mathrm{N}$ crystal structure to serve as comparison with the truncated structure. The overall RMSD numbers are larger due to minor hyperconjugative interactions along the ⁱPr ligand compared to the truncated ${\left({\mathrm{R}}^{\mathrm{a}}\right)}_3{\mathrm{NU}}^{\mathrm{VI}}\mathrm{N}$ compound.