. 2008 Dec 20;65(Pt 1):11–21. doi: 10.1107/S010876810803423X

Table 2. Possible electron redistributions for species relevant to the present work.

The Zintl–Klemm notation describes the electron redistribution, so that, in the overall electron count for the elements concerned, the superscript −1 (rather than 1−), for example, represents an excess electron on that atom; the superscript +1 represents a one-electron loss. Thus, Li⁺¹ is (Ψ-He), Al⁻¹ and N⁻¹ are (Ψ-Si) and (Ψ-O), respectively, and Al⁺³ is (Ψ-Ne).

Electron donation				Electron acceptance
3	2	1	Atom	1	2	3
N⁺³ = (Ψ-Be)	N⁺² = (Ψ-B)	N⁺¹ = (Ψ-C)	N⁰	N⁻¹ = (Ψ-O)	N⁻² = (Ψ-F)	N⁻³ = (Ψ-Ne)
	Li⁺² = (Ψ-H)	Li⁺¹ = (Ψ-He)	Li⁰	Li⁻¹ = (Ψ-Be)	Li⁻² = (Ψ-B)	Li⁻³ = (Ψ-C)
Al⁺³ = (Ψ-Ne)	Al⁺² = (Ψ-Na)	Al⁺¹ = (Ψ-Mg)	Al⁰	Al⁻¹ = (Ψ-Si)	Al⁻² = (Ψ-P)	Al⁻³ = (Ψ-S)
V⁺³ = (Ψ-Ca)	V⁺² = (Ψ-Sc)	V⁺¹ = (Ψ-Ti)	V⁰	V⁻¹ = (Ψ-Cr)	V⁻² = (Ψ-Mn)	V⁻³ = (Ψ-Fe)