An X-ray absorption spectroscopic (XAS) study has been carried out on the intercalated precursor polyhydroxy (acetato)chromium(III) alpha-zirconium phosphates, a chromia-pillared derivative obtained by calcination at 400 degrees C, and the amorphous congener obtained after calcination at 800 degrees C. The precursor solids contain interlayer hydroxy-Cr-III clusters with connnectivities of a flat dimer (12 Angstrom phase), a closed trimer (17 Angstrom phase), an open tetramer (34 Angstrom, phase), and also contain a 25 Angstrom phase with connectivity between trimer and tetramer. The acetate residues little influence the XAFS analysis, and orientations of the cluster species present between the layers are suggested on the basis of double-layer structures. The chromia-pillared material obtained after calcination of the 34 Angstrom phase has a ribbonlike structure comprising pseudo-octahedral [(CrO6)-O-III] units showing Cr---P distances (3.25 Angstrom), as expected for coordination of the pillar to the phosphate layer. There is no evidence for Cr-VI formation, unlike the oxidation that occurs on calcination in montmorillonite analogues. Amorphization at 800 degrees C causes rearrangement, and the pillar is best described as a comer-shared oxide-phosphate nanoparticle with contributions from bidentate PO43- groups. The implications for the thermal stability of oxide-pillared materials prepared using current pillaring methods are discussed.