Dehydrated aluminumdodecatungstophosphate (AlPW12O40) was investigated by Al-27 MAS NMR spectroscopy in magnetic fields of 9.4 and 17.6 T. Two kinds of octahedrally coordinated (delta(27Al) = 1-2 ppm, C-Q = 2.4-2.5 MHz, and delta(27Al) = 4-6 ppm, C-Q = 6.0-6.5 MHz), two kinds of penta-coordinated (delta(27Al) = 24-30 ppm, C-Q = 7.0-7.3 MHz, and delta(27Al) = 44 ppm, C-Q = 7.5-8.7 MHz), and a small amount of tetrahedrally coordinated aluminum cations (delta(27Al) = 65 ppm, C-Q = 8.2-8.5 MHz) were found. Comparison with H-1 MAS NMR spectroscopic studies indicates that the dehydroxylation of aluminum OH groups (delta(1H) = 4.2 ppm and 5.6 ppm) at temperatures of 473 and 573 K is accompanied by a partially irreversible change of the oxygen coordination of aluminum cations. (C) 2010 Elsevier B.V. All rights reserved.