The serendipitous discovery of CO2 as a template in the fabrication of ferric formate (1) has led to the preparation of serial metal(III) formates [M-III(HCOO)(3)center dot(3)/4CO2 center dot(1)/4H2O center dot(1)/4HCOOH ](infinity) (M = Fe(1), Al (2), Ga (3), and In(4)). The X-ray single-crystal determinations showed that the metals have octahedral geometries and are linked by HCOO- in the anti-anti style into a 3D ReO3 net, where CO2 molecules exist in cages of mmm symmetry and are hydrogen bonded to the formic CH groups. An X-ray powder diffraction (XRD) study revealed that 2 is identical to the documented [Al(HCOO)(3)center dot xH(2)O]. Further synthetic experiments and C-13 NMR spectroscopy eventually confirmed that 2 should be formulated as [Al(HCOO)(3)center dot(3)/4CO2 center dot(1)/4H2O center dot(1)/4HCOOH ](infinity), which for decades had been mistakenly given as [Al-III(HCOO)(3)center dot xH(2)O].