Morphology, crystal structure, and thermal and spectral studies of semiorganic nonlinear optical crystal LAHClBr

Solubility and specific heat properties of the semiorganic nonlinear optical crystal, L-arginine hydrocholorobromide (LAHClBr), have been measured as a function of temperature. The compound crystallizes in a rectangular bipyramidal shape with well-developed 11001 and 10011 pinacoids. X-ray diffraction analysis shows that it belongs to the space gronp P2(1) with two independent molecules in asymmetric units and lattice parameters a = 11.158(2) Angstrom, b = 8.5790 A, c = 11.2350 Angstrom, beta = 91.55degrees(4). The arginine molecules occur as zwitterions, with the amino groups and the guanidyl groups each accepting a proton from the acid groups present in the molecule. The molecules are held together by a three-dimensional network of hydrogen bonds.