Table 2. Summary of magnetic and spectral parameters for 1–3 ^a .

	1	2	3
g x b	2.00(1)	2.00(3)	2.00(1)
g y b	2.02(1)	2.07(1)	2.04(1)
g z b	2.10(4)	2.10(3)	2.08(3)
D b (cm–1)	5.21(3)	5.35(5)	5.61(9)
E b (cm–1)	0.59(2)	0.60(2)	0.59(2)
E/D b	0.11	0.11	0.10
g iso c	2.04	2.07	2.11
g iso d	2.04(1)	2.08(2)	2.07(1)
D d (cm–1)	5.6(1)	6.5(3)	5.5(2)
|E| d (cm–1)	0.5(3)	0.7(2)	0.7(1)
δ (mm s–1)	0.680(1)	0.663(1)	0.677(1)
ΔEQ (mm s–1)	4.326(2)	4.283(1)	4.330(1)

^aReported errors in EPR parameters were estimated by variance in quality of the simulation of the 406.4 GHz spectrum and the resonant field vs. frequency plot as a function of parameter variance.

^bDetermined by EPR.

^cObtained from value of χ_MT at 300 K.

^dDetermined by fits of variable-temperature, variable-field χ_MT data. Errors determined by averaging over the fits to data sets collected at 0.1, 0.5, and 1 T dc applied fields.