EXPERIMENTAL CHARGE-DENSITY AND ELECTROSTATIC POTENTIAL OF TRIGLYCINE

The experimental electron density distribution in triglycine has been determined using single-crystal X-ray diffraction data at 123 K to a r esolution of (sin theta/lambda)(max) = 1.1 Angstrom(-1). Several multi polar pseudo-atom density refinements were performed against the 7238 observed data in order to estimate the net charges on the atoms. The e lectrostatic potential around the two molecules is calculated from the parameters derived from these refinements. A charge transfer between the two triglycine molecules of the asymmetric unit is discussed. Crys tal data: C6H11N3O4, M-r = 189.2, triclinic, P (1) over bar, Z = 4 (tw o molecules in the asymmetric unit), T = 123 K, a = 11.585 (1), b = 14 .603 (2), c = 4.800 (4) Angstrom, alpha = 89.28 (3), beta = 95.55 (2), gamma = 104.484 (8)degrees, V = 782.5 (7) Angstrom(3), D-x = 1.61 g c m(-3), mu = 1.5 cm(-1) for lambda(Mo) = 0.7107 Angstrom.