Structure and bonding of pentaaquanitrosylchromium(2+) sulfate

The crystal structure of [Cr(H 2 O) 5 NO]SO 4 has been determined. The complex crystallizes in the monoclinic space group P2 1 /n with a=12.058(3) A, b=6.846(1) A, c=11.382(3) A, β=110.14(2) o , Z=4, and R (R w )=0.33 (0.045) for 1854 reflections with I≥3σ(I). The structural data are incompatible with an oxidation state of+1, which has previously been assigned to the chromium atom, and support the formulation of this compound am a chromium(III) complex of NO -