TABLE 5.

Metal-ligand bond lengths and BVS values from EXAFS and crystal structures

The first value in each line is from EXAFS, and the values in parentheses are from the crystal structures. The following abbreviations are used: Red, reduced, anaerobically prepared samples; xpr, aerobically prepared, x-ray photoreduced samples; ox, oxidized, aerobically prepared samples.

	Fe/Mn–Fe (Å)			Fe/Mn–N/O mean (Å)			BVS
	Red	xpr	Ox	Red	xpr	Ox	Red	xpr	Ox
Fe/Fe	3.64 (3.61a )	3.46 (-)	3.42 (3.52)	2.10 (2.06)	2.06 (-)	2.00 (2.06)	2.4 (2.3b)	2.6 (-)	3.1 (2.3b)
Mn/Fe	3.65 (3.61)	3.47 (-)	3.51 (3.48)	2.18 (2.05)	2.10 (-)	2.05 (2.14)	2.1 (2.5b)	2.6 (-)	3.0 (1.9b)

^a Average of chains A and B is shown.

^b Unrealistically short Fe/Mn–O distances (≤1.72 Å) in the crystal structures were replaced by average bond lengths of the remaining Fe/Mn–N/O distances in the BVS calculations.