scholarly journals High-pressure structural study of L-α-glutamine and the use of Hirshfeld surfaces and graph-set notation to investigate the hydrogen bonding present in the structure up to 4.9 GPa

2008 ◽  
Vol 64 (4) ◽  
pp. 466-475 ◽  
Author(s):  
P. Lozano-Casal ◽  
D. R. Allan ◽  
S. Parsons

The crystal structure of L-α-glutamine has been elucidated at room temperature at pressures between 0 and 4.9 GPa by using single-crystal high-pressure X-ray diffraction techniques. The structure is primarily stabilized by five N—H...O intermolecular interactions, which link molecules in a herringbone-like layer arrangement, giving rise to voids within the solid. The application of pressure on the structure results in a reduction in the size of the voids, as a consequence of the shortening of the N—H...O hydrogen bonds, which compress to minimum N...O distances of around 2.6 Å, without driving the crystal structure to a phase transition. The decrease in the hydrogen-bond distances is due to the necessary stabilization of the structure, which arises from molecules modifying their positions to optimize electrostatic contacts and minimize the occupied space. Hirshfeld surfaces and fingerprint plots have been used to rapidly assess the structural changes that occur on application of pressure.

Author(s):  
Davide Comboni ◽  
Tomasz Poreba ◽  
Francesco Pagliaro ◽  
Tommaso Battiston ◽  
Paolo Lotti ◽  
...  

The crystal structure of the high-pressure polymorph of meyerhofferite, ideally Ca2B6O6(OH)10·2(H2O), has been determined by means of single-crystal synchrotron X-ray diffraction data. Meyerhofferite undergoes a first-order isosymmetric phase transition to meyerhofferite-II, bracketed between 3.15 and 3.75 GPa, with a large volume discontinuity. The phase transition is marked by an increase in the coordination number of the boron B1 site, from III to IV, leading to a more interconnected and less compressible structure. The main structural differences between the two polymorphs and the P-induced deformation mechanisms at the atomic scale are discussed.


2014 ◽  
Vol 28 (25) ◽  
pp. 1450168 ◽  
Author(s):  
Nirup Bandaru ◽  
Ravhi S. Kumar ◽  
Jason Baker ◽  
Oliver Tschauner ◽  
Thomas Hartmann ◽  
...  

Structural behavior of bulk WS 2 under high pressure was investigated using synchrotron X-ray diffraction and diamond anvil cell up to 52 GPa along with high temperature X-ray diffraction and high pressure Raman spectroscopy analysis. The high pressure results obtained from X-ray diffraction and Raman analysis did not show any pressure induced structural phase transformations up to 52 GPa. The high temperature results show that the WS 2 crystal structure is stable upon heating up to 600°C. Furthermore, the powder X-ray diffraction obtained on shock subjected WS 2 to high pressures up to 10 GPa also did not reveal any structural changes. Our results suggest that even though WS 2 is less compressible than the isostructural MoS 2, its crystal structure is stable under static and dynamic compressions up to the experimental limit.


2006 ◽  
Vol 62 (2) ◽  
pp. 310-320 ◽  
Author(s):  
Stephen A. Moggach ◽  
David R. Allan ◽  
Simon Parsons ◽  
Lindsay Sawyer

The crystal structure of α-glycylglycine (α-GLYGLY) has been determined at room temperature at pressures between 1.4 and 4.7 GPa. The structure can be considered to consist of layers. The arrangement of molecules within each layer resembles the antiparallel β-sheet motif observed in proteins, except that in α-GLYGLY the motif is constructed through NH...O hydrogen bonds rather than covalent amide links. Compression of α-GLYGLY proceeds via the reduction in void sizes. Voids close in such a way as to decrease the distances of stabilizing interactions such as hydrogen bonds and dipolar contacts. The largest reductions in interaction distances tend to occur for those contacts which are longest at ambient pressure. These longer interactions are formed between the β-sheet-like layers, and the largest component of the strain tensor lies in the same direction. The N...O distance in one NH...O hydrogen bond measures 2.624 (9) Å at 4.7 GPa. This is very short for this kind of interaction and the crystal begins to break up above 5.4 GPa, presumably as the result of a phase transition. The changes that occur have been analysed using Hirshfeld surfaces. Changes in the appearance of these surfaces enable rapid assessment of the structural changes that occur on compression.


1989 ◽  
Vol 22 (1) ◽  
pp. 61-63 ◽  
Author(s):  
J. S. Olsen ◽  
L. Gerward ◽  
U. Benedict ◽  
H. Luo ◽  
O. Vogt

High-pressure X-ray diffraction studies have been performed on ThP using synchrotron radiation and a diamond-anvil cell. The bulk modulus B 0 and its pressure derivative B′0 have been determined (B 0 = 137 GPa; B′0 = 5.1). A phase transition from the NaCl structure to the CsCl structure was observed at about 30 GPa.


2005 ◽  
Vol 19 (06) ◽  
pp. 313-316
Author(s):  
X. M. QIN ◽  
Y. YU ◽  
G. M. ZHANG ◽  
F. Y. LI ◽  
J. LIU ◽  
...  

In-situ high-pressure energy dispersive X-ray diffraction measurements on CuBa 2- Ca 3 Cu 4 O 10 + δ (Cu-1234) have been performed by using diamond anvil cell (DAC) device with synchrotron radiation. The results suggest that the crystal structure of Cu-1234 superconductor is stable under pressures up to 34 GPa at room temperature. According to the Birch–Murnaghan equation of state, the bulk modulus is obtained to be ~ 150 GPa.


2017 ◽  
Vol 72 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Daniela Vitzthum ◽  
Michael Schauperl ◽  
Klaus R. Liedl ◽  
Hubert Huppertz

AbstractOrthorhombic In3B5O12 was synthesized in a Walker-type multianvil apparatus under high-pressure/high-temperature conditions of 12.2 GPa and 1500°C. Its structure is isotypic to the rare earth analogs RE3B5O12 (RE=Sc, Er–Lu). In the field of indium borate chemistry, In3B5O12 is the third known ternary indium borate besides InBO3 and InB5O9. The crystal structure of In3B5O12 has been determined via single-crystal X-ray diffraction data collected at room temperature. It crystallizes in the orthorhombic space group Pmna with the lattice parameters a=12.570(2), b=4.5141(4), c=12.397(2) Å, and V=703.4(2) Å3. IR and Raman bands of In3B5O12 were theoretically determined and assigned to experimentally recorded spectra.


2010 ◽  
Vol 65 (10) ◽  
pp. 1206-1212 ◽  
Author(s):  
Almut Haberer ◽  
Reinhard Kaindl ◽  
Hubert Huppertz

The praseodymium orthoborate λ -PrBO3 was synthesized from Pr6O11, B2O3, and PrF3 under high-pressure / high-temperature conditions of 3 GPa and 800 °C in a Walker-type multianvil apparatus. The crystal structure was determined on the basis of single-crystal X-ray diffraction data, collected at room temperature. The title compound crystallizes in the orthorhombic aragonite-type structure, space group Pnma, with the lattice parameters a = 577.1(2), b = 506.7(2), c = 813.3(2) pm, and V = 0.2378(2) nm3, with R1 = 0.0400 and wR2 = 0.0495 (all data). Within the trigonal-planar BO3 groups, the average B-O distance is 137.2 pm. The praseodymium atoms are ninefold coordinated by oxygen atoms.


2015 ◽  
Vol 29 (25n26) ◽  
pp. 1542024 ◽  
Author(s):  
W. M. Li ◽  
Q. Q. Liu ◽  
Y. Liu ◽  
S. M. Feng ◽  
X. C. Wang ◽  
...  

The [Formula: see text] sample with the nominal composition was synthesized. Powder X-ray diffraction (XRD) experiments confirm that it crystallizes in an orthorhombic structure with space group Immm. The synchrotron powder XRD results suggest that the crystal structure of [Formula: see text] keeps stable under pressure up to 34 GPa at room temperature with nearly isotropic compressibility. The equation of state for [Formula: see text] was obtained. The results offer opportunities to further synthesize and research [Formula: see text] superconductor with tetragonal [Formula: see text] structure.


2011 ◽  
Vol 66 (2) ◽  
pp. 107-114 ◽  
Author(s):  
Stephanie C. Neumair ◽  
Johanna S. Knyrim ◽  
Oliver Oeckler ◽  
Reinhard Kaindl ◽  
Hubert Huppertz

The cubic iron hydroxy boracite Fe3B7O13OH・1.5H2O was synthesized from Fe2O3 and B2O3 under high-pressure/high-temperature conditions of 3 GPa and 960 °C in a modified Walker-type multianvil apparatus. The crystal structure was determined at room temperature by X-ray diffraction on single crystals. It crystallizes in the cubic space group F4̄3c (Z = 8) with the parameters a = 1222.4(2) pm, V = 1.826(4) nm3, R1 = 0.0362, and wR2 = 0.0726 (all data). The B-O network is similar to that of other cubic boracites.


2008 ◽  
Vol 63 (6) ◽  
pp. 707-712 ◽  
Author(s):  
Johanna S. Knyrim ◽  
Hubert Huppertz

The high-pressure phase β -ZrB2O5 represents the first ternary borate in the system Zr-B-O. The compound was synthesized under high-pressure / high-temperature conditions of 7.5 GPa and 1100 °C in a Walker-type multianvil apparatus. The crystal structure was determined on the basis of single crystal X-ray diffraction data, collected at room temperature. The monoclinic zirconium borate crystallizes in the space group P21/c with the lattice parameters a = 439.04(9), b = 691.2(2), c = 896.8(2) pm, and β = 90.96(3)°. The structure is isotypic to the high-pressure phase β -HfB2O5, which is built up from layers of exclusively corner-sharing BO4 tetrahedra. Between these layers, the cations are coordinated square-antiprismatically by eight oxygen atoms.


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