Morpholin-4-ium hydrogen l-tartrate monohydrate

In the title compound, C4H10NO+·C4H5O6 −·H2O, the morpholine ring adopts a chair conformation. In the crystal, the tartrate anions are linked via O—H⋯O hydrogen bonds, forming chains propagating along [101]. These chains are linked via N—H⋯O and O—H⋯O hydrogen bonds, involving the morpholinium cation and the water molecule, forming a three-dimensional network.

In the title compound, C 4 H 10 NO + ÁC 4 H 5 O 6 À ÁH 2 O, the morpholine ring adopts a chair conformation. In the crystal, the tartrate anions are linked via O-HÁ Á ÁO hydrogen bonds, forming chains propagating along [101]. These chains are linked via N-HÁ Á ÁO and O-HÁ Á ÁO hydrogen bonds, involving the morpholinium cation and the water molecule, forming a three-dimensional network.

Experimental
Cold absolute methanol (60 ml) was added to L-tartaric acid (2.94 g, 19.62mmol). The acid was dissolved by heating the mixture on a hot plate with stirring maintained at a temperature of 358 K. The solution was cooled to 298 K and morpholine (1.70 g, 19.62 mmol) was added dropwise. The product was precipitated out of the solution as a white tiny seed crystals by spontaneous nucleation (78.3 %, m.p. 441-442 K). Single crystals suitable for X-ray diffraction were recrystallized ethl alcohol.

Refinement
The H atoms bonded to O1w were located a different Fourier map and refined freely. All other H atoms were positioned geometrically, with C-H = 0.93 and N-H = 0.89Å constrained to ride on their parent atoms, with U iso (H) = xU eq (C, N), where x = 1.5 for methyl H and x = 1.2 for all other H atoms. Fig. 1. The molecular structure of the title compound with the atom numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are presented as small spheres of arbitrary radius.

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2sigma(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.