Table 1.

$d^n$ configuration ${(d}_{\alpha }^{occ}+d_{\beta }^{occ})$ and number of unpaired electrons in d-shell $(d_{\alpha }^{occ}-d_{\beta }^{occ})$ obtained by Mulliken population analysis for DFTB3, DFTB3+U (F⁰=0.035) and OPBE, together with atomic values. ^a

number of electrons in d-shell
	${\mathit{d}}^{\mathit{n}}={\mathit{d}}_{\mathit{\alpha }}^{\mathit{o}\mathit{c}\mathit{c}}+{\mathit{d}}_{\mathit{\beta }}^{\mathit{o}\mathit{c}\mathit{c}}$				$\mathit{u}\mathit{n}\mathit{p}\mathit{a}\mathit{i}\mathit{r}\mathit{e}\mathit{d}\mathit{e}\mathit{l}\mathit{e}\mathit{c}.={\mathit{d}}_{\mathit{\alpha }}^{\mathit{o}\mathit{c}\mathit{c}}-{\mathit{d}}_{\mathit{\beta }}^{\mathit{o}\mathit{c}\mathit{c}}$
	Ni(II)		Ni(III)		Ni(II)		Ni(III)
	HS	LS	HS	LS	HS	LS	HS	LS
atomic values	d8	d8	d7	d7	2	0	3	1
DFTB3	d8.9	d9.0	d8.7	d8.8	1.0	0	1.2	0.4
xTB	d8.6	d8.7	d8.4	d8.4	1.3	0	1.6	0.6
DFTB3+U	d7.8	d8.0	d7.5	d7.7	1.7	0	2.2	0.9
OPBE	d8.3	d8.5	d8.2	d8.2	1.3	0	1.5	0.8

^aThe values are averages for all Ni(II) and Ni(III) compounds studied here; for individual molecules, see SI (Tables S1, S2). Mulliken population analysis is used for all methods.