The layered double hydroxide (LDH) Al 2 Li(OH) 6 [NiCl 4 ] (sub 1/2) was synthesized by anion exchange of Al 2 Li(OH) 6 (NO 3 ) and the coordination structure of [NiCl 4 ] (super 2-) in the interlayers was investigated. The LDH had a hexagonal cell with a = 5.06 and c = 23.06 Aa. Since the basal spacing of one layer was 7.7 Aa, the interlayer distance was calculated to be 2.9 Aa and was too narrow for the usual tetrahedral NiCl 4 structure. From extended X-ray absorption fine structure (EXAFS) measurements, the first neighbour Ni-Cl distances in the LDH were 2.10 Aa which was compatible with four-fold coordination. Since the electron spin resonance (ESR) spectrum of the LDH showed no absorption, the [NiCl 4 ] (super 2-) structure was considered to be square planar, rather than the usual tetrahedral structure in the interlayers of LDH.