organic compounds
Precise X-ray determinations of the crystal structure of the 1:2 complex of N-ethyl-N-methylmorpholinium and 7,7,8,8-tetracyano-p-quinodimethanide, abbreviated as MEM-TCNQ or MEM(TCNQ)2 (C7H16NO+·2C12H4N40.5-), have been performed at 293 and at 10 K. Evidence for the expected spin-Peierls transition at 19 K is not found, and this may follow from radiation damage to the crystal or from insufficient equipment sensitivity.