Key indicators: single-crystal X-ray study; T = 293 K; mean (C-C) = 0.002 Å; R factor = 0.052; wR factor = 0.132; data-to-parameter ratio = 11.1. The title compound, C 12 H 10 O 5 , was prepared as part of our study on obtaining pure regioselective Friedel-Crafts acetylation products. The molecule is planar with no hydrogen bonds found in the crystal structure. The molecules are stacked together throughinteractions (centroid-centroid distance = 3.655 Å ), with the stacks of molecules forming a

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... igzag packing arrangement stabilized by van der Waals forces. Related literature For regioselective Friedel-Crafts acetylation reactions, see: Mata & Suá rez (1997); Thié ry et al. (1995). For related structures, see: Leger et al. (1983). Experimental Crystal data C 12 H 10 O 5 M r = 234.20 Monoclinic, P2 1 =c a = 7.2282 (11) Å b = 25.147 (4) Å c = 5.9639 (9) Å = 103.598 (3) V = 1053.6 (3) Å 3 Z = 4 Mo K radiation = 0.12 mm À1 T = 293 (2) K 0.52 Â 0.23 Â 0.18 mm Data collection Bruker SMART CCD area-detector diffractometer Absorption correction: multi-scan (SADABS; Sheldrick, 1996) T min = 0.757, T max = 1.000 (expected range = 0.741-0.979) 5915 measured reflections 2172 independent reflections 1409 reflections with I > 2(I) R int = 0.079 Refinement R[F 2 > 2(F 2 )] = 0.052 wR(F 2 ) = 0.132 S = 0.92 2172 reflections 195 parameters H atoms treated by a mixture of independent and constrained refinement Á max = 0.22 e Å À3 Á min = À0.21 e Å À3