Table 3. Compounds used in covalency analysis, comparing experimentally derived % N 2p character, according to eqn (1), in first N K-edge XAS pre-edge feature.

Compound a	Total pre-edge area (D0)	#Absorbers (n)	#Holes (h)	Calc %N 2p (α2)	Experimental %N 2p (α2) method A	Experimental %N 2p (α2) method B
[Co(NH3)5Cl]2+	1.21 ± 0.07	5	4	17	17.8 ± 1.6	16.9 ± 1.6
[Ni(NH3)6]2+	0.29 ± 0.06	6	2	12	10.4 ± 2.3	9.9 ± 2.2
[Cu(NH3)4]2+	0.62 ± 0.05	4	1	25	27.2 ± 2.8 b	25.0 c
[Cu(en)2]2+	0.50 ± 0.01	4	1	25	25.5 ± 1.8 b	25.0 c
[Zn(en)3]2+	0.17 ± 0.08	6	2	9	6.1 ± 2.9	5.8 ± 2.7
[Mn(bpy)3]2+	1.89 ± 0.03	6	6	20	22.4 ± 1.5	21.2 ± 1.5
[Fe(bpy)3]2+	1.87 ± 0.04	6	6	19	22.1 ± 1.6	20.9 ± 1.6
[Co(bpy)3]2+	1.68 ± 0.05	6	6	21	19.8 ± 1.4	18.8 ± 1.4
[Co(bpy)3]3+	2.01 ± 0.06	6	6	20	23.8 ± 1.7	22.5 ± 1.7
[Ni(bpy)3]2+	2.47 ± 0.09	6	6	25	29.1 ± 2.2	27.6 ± 2.2
[Zn(bpy)3]2+	2.0 ± 0.2	6	6	20	24.1 ± 2.5	22.8 ± 2.4
[Ru(bpy)3]2+	1.82 ± 0.08	6	6	21	21.5 ± 1.7	20.4 ± 1.7
[Rh(bpy)3]3+	2.00 ± 0.02	6	6	20	23.6 ± 1.6	22.3 ± 1.6
[Os(bpy)3]2+	2.15 ± 0.09	6	6	20	25.4 ± 2.0	24.0 ± 2.0
[ReNCl4]1–	5.4 ± 0.2	2 d	4	30	32.1 ± 2.6	30.4 ± 2.5
[OsNCl4]1–	6.20 ± 0.06	2 d	4	34	36.6 ± 2.5	34.7 ± 2.5

^aComplete formulations including counterions given in the ESI.

^bDetermined via Cu L_2,3-edge XAS.

^cDetermined via B3LYP/ZORA-def2-TZVP(-f) calculations.

^dNecessary to set n = 2 in order to account for absorption contributions from the ⁿBu₄N⁺ counterion.