Chemistry Letters, Vol.30, No.10, 1008-1009, 2001
Crystal structure of 2,6-dimethylpyridinium hydrogen fumarate: Hydrogen bonds of C(sp(3))-H center dot center dot center dot O, C(sp(2))-H center dot center dot center dot O and N+-H center dot center dot O-(sp(3))
X-ray diffraction study on 2,6-dimethylpyridinium hydrogen fumarate reveals that the same site of O-(sp(3)) is confined by hydrogen bonds not only of N+-H...O-, but also those of C(sp(3))-H...O and C(sp(2))-H...O.