. 2015 Feb 25;119(11):5888–5902. doi: 10.1021/acs.jpcc.5b00557

Table 1. Most Relevant Structural and Bonding Parameters of the LS and HS States of [Fe(terpy)₂]²⁺^a.

	LS (¹A₁)		HS (⁵E)	HS (⁵B₂)
	exptl⁶⁶	calculated
R(Fe–N_ax)	1.891(5) Å	1.886 Å	2.103 Å	2.159 Å
R(Fe–N_eq)	1.988(10) Å	1.985 Å	2.198 Å	2.187 Å
NNN angle	102.8(3)°	102.6°	108.4°	107.2°
B_{FeN_ax}	-	0.65	0.39	0.33
B_{FeN_eq}	-	0.60	0.34	0.34

The experimental data are taken from ref (66). The calculations were carried out at the DFT BP86/TZVP level (for the ⁵E at the (relaxed) JT-distorted geometry). BAB denotes the Mayer bond order index, a powerful parameter quantifying the strength of chemical bonds between atoms A and B (based on MO coefficients and overlaps).^37,39,67

Table 1. Most Relevant Structural and Bonding Parameters of the LS and HS States of [Fe(terpy)2]2+a.

Table 1. Most Relevant Structural and Bonding Parameters of the LS and HS States of [Fe(terpy)₂]²⁺^a.