Hydrogen positions in potassium pentaborate tetrahydrate as determined by neutron diffraction

1970 ◽  
Vol 48 (9) ◽  
pp. 1091-1097 ◽  
Author(s):  
J. P. Ashmore ◽  
H. E. Petch
Keyword(s):  
Neutron Diffraction ◽  
Water Molecule ◽  
Least Squares ◽  
Single Crystals ◽  
Diffraction Data ◽  
Hydroxyl Groups ◽  
Neutron Diffraction Data ◽  
Hydrogen Atoms ◽  
X Ray ◽  
Atomic Coordinates

Neutron diffraction data obtained with single crystals of potassium pentaborate tetrahydrate have been analyzed using least squares methods. Apart from significant differences in the atomic coordinates of the hydrogen atoms, the structure is in agreement with recent X-ray work. The O—H distances in the hydroxyl groups are 1.012 ± 0.018 and 0.955 ± 0.020 Å. In contrast to the X-ray results, the geometry of the water molecule is normal for an inorganic hydrate with O—H distances of 0.954 ± 0.026 and 1.004 ± 0.018 Å and an H—O—H angle of 108 ± 2°.

The crystal and molecular structure of the platinum(0) complex, [CH3C(CH2PPh2)3]2Pt

1977 ◽  
Vol 30 (11) ◽  
pp. 2407 ◽  
Author(s):  
FC March ◽  
R Mason ◽  
GR Scollary
Keyword(s):  
Molecular Structure ◽  
Metal Complexes ◽  
Least Squares ◽  
Single Crystals ◽  
Diffraction Data ◽  
Crystal And Molecular Structure ◽  
Hydrogen Atoms ◽  
Triclinic Space Group ◽  
X Ray ◽  
The Past

An X-ray analysis of single crystals of bis[1,1,1- tris(diphenylphosphinomethyl)ethane]platinum(O) is described. The crystals are triclinic, space group Aī, a 15.018(5), b 25.937(9), c 22.722(8) Ǻ; α 104.16(2)�, β 115.80(2)�, γ 88.65(2)�, Z4. ��� The diffraction data (Mo Kα; automatic diffractometry) have provided all atomic positions (with the exception of hydrogen atoms) and the scattering model has been refined by least-squares methods to R 0.084 (4774 independent reflections). The platinum has a distorted tetrahedral stereochemistry (with mean Pt-P 2.287 Ǻ), only four of the six phosphorus ligand atoms being coordinated. This stereochemistry is preserved in solution. A discussion of the metal-phosphorus bond in low-valent metal complexes is provided, it being concluded that π- bonding effects on bond lengths have been overemphasized in the past.

NEUTRON DIFFRACTION DETERMINATION OF THE HYDROGEN POSITIONS IN NATROLITE

1964 ◽  
Vol 42 (2) ◽  
pp. 229-240 ◽  
Author(s):  
B. H. Torrie ◽  
I. D. Brown ◽  
H. E. Petch
Keyword(s):  
Hydrogen Bonds ◽  
Neutron Diffraction ◽  
Oxygen Atom ◽  
Water Molecule ◽  
Neutron Diffraction Data ◽  
X Ray Diffraction ◽  
Hydrogen Atoms ◽  
X Ray ◽  
Diffraction Determination

Neutron diffraction data obtained with single crystals of natrolite, Na2Al2Si3O10.2H20, have been analyzed using Fourier difference synthesis arid least squares methods. The details of the aluminosilicate framework were found to be in agreement with the results of earlier X-ray diffraction studies. The oxygen atom of the water molecule is linked by bent hydrogen bonds to two oxygen atoms in the framework, making an O—O—O angle of 134°. Lying almost in the O—O—O plane, the hydrogen atoms are located at distances of 0.94 ± 0.03 and 0.98 ± 0.02 Å from the oxygen of the water molecule and make with it an H—O—H angle of 108°. Natrolite thus provides an excellent example of the ability of the water molecule to resist the influence of the environment in opening the H—O—H angle.

Design of a novel Peltier-based cooling device and its use in neutron diffraction data collection of perdeuterated yeast pyrophosphatase

2010 ◽  
Vol 43 (5) ◽  
pp. 1113-1120 ◽  
Author(s):  
Esko Oksanen ◽  
François Dauvergne ◽  
Adrian Goldman ◽  
Monika Budayova-Spano
Keyword(s):  
Data Collection ◽  
Neutron Diffraction ◽  
Diffraction Data ◽  
Catalytic Mechanism ◽  
Inorganic Pyrophosphatase ◽  
Neutron Diffraction Data ◽  
Cooling Device ◽  
Data Set ◽  
X Ray ◽  
X Ray Crystallography

H atoms play a central role in enzymatic mechanisms, but H-atom positions cannot generally be determined by X-ray crystallography. Neutron crystallography, on the other hand, can be used to determine H-atom positions but it is experimentally very challenging. Yeast inorganic pyrophosphatase (PPase) is an essential enzyme that has been studied extensively by X-ray crystallography, yet the details of the catalytic mechanism remain incompletely understood. The temperature instability of PPase crystals has in the past prevented the collection of a neutron diffraction data set. This paper reports how the crystal growth has been optimized in temperature-controlled conditions. To stabilize the crystals during neutron data collection a Peltier cooling device that minimizes the temperature gradient along the capillary has been developed. This device allowed the collection of a full neutron diffraction data set.

scholarly journals Rubidium tetrafluoridobromate(III): redetermination of the crystal structure from single-crystal X-ray diffraction data

IUCrData ◽  
2019 ◽  
Vol 4 (11) ◽  
Author(s):  
Artem V. Malin ◽  
Sergei I. Ivlev ◽  
Roman V. Ostvald ◽  
Florian Kraus
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Single Crystals ◽  
Diffraction Data ◽  
Structure Type ◽  
X Ray Diffraction ◽  
X Ray ◽  
Square Planar ◽  
Atomic Coordinates

Single crystals of rubidium tetrafluoridobromate(III), RbBrF4, were grown by melting and recrystallizing RbBrF4 from its melt. This is the first determination of the crystal structure of RbBrF4 using single-crystal X-ray diffraction data. We confirmed that the structure contains square-planar [BrF4]− anions and rubidium cations that are coordinated by F atoms in a square-antiprismatic manner. The compound crystallizes in the KBrF4 structure type. Atomic coordinates and bond lengths and angles were determined with higher precision than in a previous report based on powder X-ray diffraction data [Ivlev et al. (2015). Z. Anorg. Allg. Chem. 641, 2593–2598].

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