title: First experimental charge density study using a Bruker CMOS-type PHOTON 100 detector: the case of ammonium tetraoxalate dihydrate.
abstract: The aim of this study was to test the applicability of a Bruker AXS CMOS-type PHOTON 100 detector for the purpose of a fine charge density quality data collection. A complex crystal containing oxalic acid, ammonium oxalate and two water molecules was chosen as a test case. The data was collected up to a resolution of 1.31 Å(-1) with high completeness (89.1%; Rmrg = 0.0274). The multipolar refinement and subsequent quantum theory of atoms in molecules (QTAIM) analysis resulted in a comprehensive description of the charge density distribution in the crystal studied. The residual density maps are flat and almost featureless. It was possible to derive reliable information on intermolecular interactions to model the anharmonic motion of a water molecule, and also to observe the fine details of the charge density distribution, such as polarization on O and H atoms involved in the strongest hydrogen bonds. When compared with our previous statistical study on oxalic acid data collected with the aid of CCD cameras, the complementary metal-oxide semiconductor (CMOS) detector can certainly be classified as a promising alternative in advanced X-ray diffraction studies.
authors.affiliation: Czochralski Laboratory of Advanced Crystal Engineering, Biological and Chemical Research Centre, Department of Chemistry, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland.
authors.forename: Katarzyna N
authors.initials: KN
authors.lastname: Jarzembska
authors.affiliation: Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, NY 14260-3000, USA.
authors.forename: Radosław
authors.initials: R
authors.lastname: Kamiński
authors.affiliation: Czochralski Laboratory of Advanced Crystal Engineering, Biological and Chemical Research Centre, Department of Chemistry, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland.
authors.forename: Lukasz
authors.initials: L
authors.lastname: Dobrzycki
authors.affiliation: Czochralski Laboratory of Advanced Crystal Engineering, Biological and Chemical Research Centre, Department of Chemistry, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland.
authors.forename: Michał K
authors.initials: MK
authors.lastname: Cyrański
mesh_terms: D064751:Ammonium Compounds / Q000737:chemistry*; D018360:Crystallography, X-Ray / Q000295:instrumentation / Q000379:methods; D006860:Hydrogen Bonding; D008958:Models, Molecular; D015394:Molecular Structure; D010070:Oxalates / Q000737:chemistry*; D019815:Oxalic Acid / Q000737:chemistry*; D017785:Photons; D011789:Quantum Theory; D012666:Semiconductors; D014961:X-Ray Diffraction / Q000295:instrumentation* / Q000379:methods*
chemical_list: D064751:Ammonium Compounds; D010070:Oxalates; D019815:Oxalic Acid
keywords: CMOS technology; PHOTON100 detector; charge density distribution; quantum theory of atoms in molecules