Preparation and structural study of a novel nonlinear molecular material: the L-histidinum dihydrogenarsenate orthoarsenic acid crystal

L-Histidinium dihydrogenarsenate orthoarsenic acid (LHA) crystal; L-HistH(). H(2)ASO(4)(-). H3AsO4; belongs to P2(l) space group of the monoclinic sy stem, Z = 2, a = 9.264(2) Angstrom, b = 8.929(2) Angstrom, c = 8.874(2) Ang strom, beta = 108.61(3)degrees. The crystal is isomorphous to L - HistH(+). H2PO4. H3PO4 (LHP) crystal. The H2AsO4- anions and H3AsO4 molecules are jo ined into layers parallel to the (100) crystallographic planes by the O-H . .. O type hydrogen bonds. The histidinium cations occupy the space between the layers. The histidinium cation posses the carboxylic COO- group. The po sitive charges appear in the ring (the proton is attached to the =N(3)- nit rogen) and in the ammonium group. The differential scanning calorimetric (D SC) diagram does not show any phase transition till 100 K. The infrared spe ctrum fully confirms the X-ray crystal structure. The LHA crystal is a good second harmonic generator (0.46 relative to KDP) (C) 2000 Elsevier Science B.V. All rights reserved.