Average M–O_O2CMe (Å) bond distances determined by single crystal X-ray diffraction measurements made on (NH₄)₂M(O₂CMe)₅ (M = Eu, Am, Cm). Uncertainty is reported as the standard deviation from the mean at 1σ^a.

Compound	M–OO2CMe (Å)
(NH4)2Eu(O2CMe)5	2.46 ± 0.09
(NH4)2Am(O2CMe)5	2.50 ± 0.08
(NH4)2Cm(O2CMe)5	2.49 ± 0.08

^aThe standard deviation is high due to the mixture of (κ¹)- vs. (κ²)-coordination environments.