scholarly journals Structure, thermal expansion and incompressibility of MgSO4·9H2O, its relationship to meridianiite (MgSO4·11H2O) and possible natural occurrences

2017 ◽  
Vol 73 (1) ◽  
pp. 47-64 ◽  
Author(s):  
A. Dominic Fortes ◽  
Kevin S. Knight ◽  
Ian G. Wood
Keyword(s):  
Thermal Expansion ◽  
Bulk Modulus ◽  
Interstitial Water ◽  
Ambient Pressure ◽  
Water Molecules ◽  
Monoclinic Space Group ◽  
X Rays ◽  
Pressure Derivative ◽  
Cell Parameters ◽  
Thermal Expansion Tensor

Since being discovered initially in mixed-cation systems, a method of forming end-member MgSO4·9H2O has been found. We have obtained powder diffraction data from protonated analogues (using X-rays) and deuterated analogues (using neutrons) of this compound over a range of temperatures and pressures. From these data we have determined the crystal structure, including all hydrogen positions, the thermal expansion over the range 9–260 K at ambient pressure, the incompressibility over the range 0–1.1 GPa at 240 K and studied the transitions to other stable and metastable phases. MgSO4·9D2O is monoclinic, space group P21/c, Z = 4, with unit-cell parameters at 9 K, a = 6.72764 (6), b = 11.91154 (9), c = 14.6424 (1) Å, β = 95.2046 (7)° and V = 1168.55 (1) Å3. The structure consists of two symmetry-inequivalent Mg(D2O)6 octahedra on sites of \bar 1 symmetry. These are directly joined by a water–water hydrogen bond to form chains of octahedra parallel with the b axis at a = 0. Three interstitial water molecules bridge the Mg(D2O)6 octahedra to the SO4 2− tetrahedral oxyanion. These tetrahedra sit at a ≃ 0.5 and are linked by two of the three interstitial water molecules in a pentagonal motif to form ribbons parallel with b. The temperature dependences of the lattice parameters from 9 to 260 K have been fitted with a modified Einstein oscillator model, which was used to obtain the coefficients of the thermal expansion tensor. The volume thermal expansion coefficient, αV, is substantially larger than that of either MgSO4·7D2O (epsomite) or MgSO4·11D2O (meridianiite), being ∼ 110 × 10−6 K−1 at 240 K. Fitting to a Murnaghan integrated linear equation of state gave a zero-pressure bulk modulus for MgSO4·9D2O at 240 K, K 0 = 19.5 (3) GPa, with the first pressure derivative of the bulk modulus, K′ = 3.8 (4). The bulk modulus is virtually identical to meridianiite and only ∼ 14% smaller than that of epsomite. Above ∼ 1 GPa at 240 K the bulk modulus begins to decrease with pressure; this elastic softening may indicate a phase transition at a pressure above ∼ 2 GPa. Synthesis of MgSO4·9H2O from cation-pure aqueous solutions requires quench-freezing of small droplets, a situation that may be relevant to spraying of MgSO4-rich cryomagmas into the surface environments of icy satellites in the outer solar system. However, serendipitously, we obtained a mixture of MgSO4·9H2O, mirabilite (Na2SO4·10H2O) and ice by simply leaving a bottle of mid-winter brine from Spotted Lake (Mg/Na ratio = 3), British Columbia, in a domestic freezer for a few hours. This suggests that MgSO4·9H2O can occur naturally – albeit on a transient basis – in certain terrestrial and extraterrestrial environments.

scholarly journals Structure of magnesium selenate enneahydrate, MgSeO4·9H2O, from 5 to 250 K using neutron time-of-flight Laue diffraction

2015 ◽  
Vol 71 (3) ◽  
pp. 313-327 ◽  
Author(s):  
A. Dominic Fortes ◽  
Dario Alfè ◽  
Eduardo R. Hernández ◽  
Matthias J. Gutmann
Keyword(s):  
Density Functional ◽  
Crystal Morphology ◽  
Water Molecules ◽  
Monoclinic Space Group ◽  
Single Crystal Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
Cell Parameters ◽  
Diffraction Structure ◽  
Neutron Time

The complete structure of MgSeO4·9H2O has been refined from neutron single-crystal diffraction data obtained at 5, 100, 175 and 250 K. It is monoclinic, space groupP21/c,Z= 4, with unit-cell parametersa= 7.222 (2),b= 10.484 (3),c= 17.327 (4) Å, β = 109.57 (2)°, andV= 1236.1 (6) Å3[ρcalc= 1770 (1) kg m−3] at 5 K. The structure consists of isolated [Mg(H2O)6]2+octahedra, [SeO4]2−tetrahedra and three interstitial lattice water molecules, all on sites of symmetry 1. The positions of the H atoms agree well with those inferred on the basis of geometrical considerations in the prior X-ray powder diffraction structure determination: no evidence of orientational disorder of the water molecules is apparent in the temperature range studied. Six of the nine water molecules are hydrogen bonded to one another to form a unique centrosymmetric dodecamer, (H2O)12. Raman spectra have been acquired in the range 170–4000 cm−1at 259 and 78 K;ab initiocalculations, using density functional theory, have been carried out in order to aid in the analysis of the Raman spectrum as well as providing additional insights into the geometry and thermodynamics of the hydrogen bonds. Complementary information concerning the thermal expansion, crystal morphology and the solubility are also presented.

Synthesis and structural characterization of BaV4O9

2007 ◽  
Vol 63 (2) ◽  
pp. 270-276 ◽  
Author(s):  
Thomas Reeswinkel ◽  
Sebastian Prinz ◽  
Karine M. Sparta ◽  
Georg Roth
Keyword(s):  
Crystal Structure ◽  
Thermal Expansion ◽  
Structural Characterization ◽  
Room Temperature ◽  
Monoclinic Space Group ◽  
Temperature Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermal Expansion Tensor

The new spin ½ V4+ barium oxovanadate BaV4O9 was synthesized and studied by means of single-crystal X-ray diffraction. Its room-temperature structure is monoclinic, space group P2/c. We discuss the temperature evolution of the crystal structure and thermal expansion tensor of the material between 293 and 100 K.

Synthesis and crystal structure of the lanthanum cyanurate complex La[H2N3C3O3]3 · 8.5 H2O

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Olaf Reckeweg ◽  
Falk Lissner ◽  
Thomas Schleid
Keyword(s):  
Interstitial Water ◽  
Cyanuric Acid ◽  
Dead Volume ◽  
Water Molecules ◽  
Ambient Conditions ◽  
Slow Cooling ◽  
Triclinic Space Group ◽  
Synthesis And Crystal Structure ◽  
X Ray ◽  
Cell Parameters

Abstract Single crystals of La[H2N3C3O3]3 · 8.5 H2O were obtained from stoichiometric amounts of as-precipitated La(OH)3 with cyanuric acid (CYA) [H3N3C3O3]3 in a boiling aqueous solution, followed by slow cooling and evaporation of water under ambient conditions. According to the X-ray structure analysis of the colorless and transparent crystals, La[H2N3C3O3]3 · 8.5 H2O adopts the triclinic space group P1 (no. 1) and exhibits the unit-cell parameters a = 987.24(7), b = 1110.97(8), c = 1179.81(9) pm, α = 113.716(2), β = 97.053(2), γ = 101.502(2)° for Z = 2. The CYA is singly deprotonated to give monoanions [H2N3C3O3]– which are O,N-coordinated to the La3+ cations. These dihdrogencyanurate anions are assembled in ribbons with two crystallographically different La3+ cations coordinating to either one or two different ligands, respectively. The coordination sphere of the La3+ cations is comprised of water molecules, and interstitial water molecules fill the dead volume of the crystals. The anionic ribbons are stacked to maximize the contact between the six-membered rings, showing distances of about 330 pm.

Powder diffraction data for N,N'-diphenylguanidinium nitrate at room and low temperatures

2006 ◽  
Vol 21 (3) ◽  
pp. 241-244
Author(s):  
Pedro Pereira Silva ◽  
Manuela Ramos Silva ◽  
José António Paixão ◽  
Ana Matos Beja
Keyword(s):  
Thermal Expansion ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Unit Cell ◽  
Powder Diffraction Data ◽  
Unit Cell Parameters ◽  
Orthorhombic Space Group ◽  
Cell Parameters ◽  
Thermal Expansion Tensor ◽  
Atomic Parameters

X-ray powder diffraction data for N,N'-diphenylguanidinium nitrate, within the temperature range of 103–293 K, are reported. The pattern at 293 K was confirmed by a fitting of the overall parameters performed with FULLPROF using the atomic parameters obtained from single-crystal studies. The compound is orthorhombic, space group Pna21 (33), with unit-cell parameters a=1.7058(4) nm, b=1.3933(3) nm, c=0.5821(1) nm, and V=1.3834(6) nm3. The unit-cell parameters for the other six temperatures measured were determined by performing pattern matching with FULLPROF. The unit-cell volume contracted on cooling from 1.3834(6) nm3 to 1.3403(4) nm3. The thermal expansion tensor was calculated from the changes of the unit-cell parameters with temperature. The elements of the thermal expansion tensor at 293 K are α11=125(4),α22=57(9), and α33=82(3)×10−6 K−1.

Thermal expansion of andalusite and sillimanite at ambient pressure: a powder X-ray diffraction study up to 1000°C

2011 ◽  
Vol 75 (2) ◽  
pp. 363-374 ◽  
Author(s):  
X. Hu ◽  
X. Liu ◽  
Q. He ◽  
H. Wang ◽  
S. Qin ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Invariant Point ◽  
Ambient Pressure ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Thermal Expansion Data ◽  
X Ray ◽  
Cell Parameters ◽  
Polynomial Expression

AbstractThe unit-cell parameters of andalusite and sillimanite have been measured by high-T powder X-ray diffraction up to 1000°C at ambient pressure. Within the temperature range investigated, all the unit-cell parameters varied smoothly, indicating no phase transition. The volume-temperature data were fitted with a polynomial expression for the thermal expansion coefficient (αT = a0 + a1T + a2T-2). yielding a0 = 2.55(2) × 10–5K–1, al = 0 and a2 = 0 for andalusite, and a0 = 1.40(4) × 10–5K–1a1 = 7.1(8) × 10–9K–2 and a2 = 0 for sillimanite. Using the new thermal expansion data determined in the present study and compressional data from the literature, the P-T phase relations of the kyanite-andalusite-sillimanite system were calculated thermodynamically, with the invariant point located at ∼523°C and 3.93 kbar.

Structural and thermal properties of the monoclinic Lu2SiO5single crystal: evaluation as a new laser matrix

2009 ◽  
Vol 42 (2) ◽  
pp. 284-294 ◽  
Author(s):  
Hengjiang Cong ◽  
Huaijin Zhang ◽  
Jiyang Wang ◽  
Wentao Yu ◽  
Jiandong Fan ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Thermal Conductivity ◽  
Heat Capacity ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
Specific Heat ◽  
Linear Thermal Expansion ◽  
Cell Parameters ◽  
Thermal Expansion Tensor ◽  
Anisotropic Thermal Conductivity

The crystal structure of monoclinic Lu2SiO5(LSO) crystals, grown by the Czochralski method, was determined at room temperature by X-ray diffraction. The unit-cell parameters area= 10.2550 (2),b= 6.6465 (2),c= 12.3626 (4) Å, β = 102.422 (1)° in space groupI2/a. The linear thermal expansion tensor was determined along thea,b,candc* directions over the temperature range from 303.15 to 768.15 K, and the principal coefficients of the thermal expansion tensor are found to be αI= −1.0235 × 10−6 K, αII= 4.9119 × 10−6 K and αIII= 10.1105 × 10−6 K. The temperature dependence of the cell volume and monoclinic angle were also evaluated. In addition, the specific heat and the thermal diffusivity were measured over the temperature ranges from 293.15 to 673.15 K and from 303.15 to 572.45 K, respectively. As a result, the anisotropic thermal conductivity could be calculated and is reported for the first time, to the best of the authors' knowledge. The specific heat capacity of LSO is 139.54 J mol−1 K−1, and the principal components of the thermal conductivity arekI= 2.26 W m−1 K−1,kII= 3.14 W m−1 K−1andkII= 3.67 W m−1 K−1at 303.15 K. A new structure model was proposed to better understand the relationships between the crystal structure and anisotropic thermal properties. In comparison with other laser matrix crystals, it is found that LSO possesses relatively large anisotropic thermal properties, and owing to its small heat capacity it has a moderate thermal conductivity, which is similar to those of the tungstates but lower than those of the vanadates.

Energetic materials: variable-temperature crystal structure of β-NTO

2003 ◽  
Vol 36 (2) ◽  
pp. 280-285 ◽  
Author(s):  
Nadezhda B. Bolotina ◽  
Elizabeth Zhurova ◽  
A. Alan Pinkerton
Keyword(s):  
Crystal Structure ◽  
Thermal Expansion ◽  
Energetic Materials ◽  
Variable Temperature ◽  
Thermal Motion ◽  
X Ray Diffraction ◽  
Cell Parameters ◽  
Thermal Expansion Tensor ◽  
Principal Axes ◽  
Molecular Dynamics Calculations

The crystal structure of the metastable β form of 5-nitro-2,4-dihydro-3H-1,2,4-triazol-3-one (β-NTO, monoclinic,P21/c) has been investigated at five temperatures in the range 100–298 K using single-crystal X-ray diffraction techniques. The second-rank thermal expansion tensor has been determined to describe thermal behavior of the crystal. The most significant thermal expansion is in a plane, which is almost perpendicular to the planes of all the NTO molecules. Perpendicular to the plane of maximal thermal expansion, a modest thermal contraction takes place. Both thermal expansion and contraction of the crystal lattice indicate anharmonicity of the atomic thermal motion. The experimental thermal variation of the unit-cell parameters is in qualitative agreement with that previously obtained from molecular dynamics calculations. Rigid-body analysis of the molecular thermal motion was performed using the libration and translation second-rank tensors. Although the translation part of the thermal motion is not strongly anisotropic, the largest displacements of the NTO molecules are oriented in the plane of maximal thermal expansion of the crystal and have significant anharmonic components. The libration motion is more anisotropic, and the largest libration as well as the largest translation principal axes are directed along the C5—N5 bond in each NTO molecule.

Expression, purification and crystallization of the catalytic subunit of protein kinase CK2 from Zea mays

1998 ◽  
Vol 54 (1) ◽  
pp. 143-145 ◽  
Author(s):  
Barbara Guerra ◽  
Karsten Niefind ◽  
Lorenzo A. Pinna ◽  
Dietmar Schomburg ◽  
Olaf-Georg Issinger
Keyword(s):  
Protein Kinase ◽  
Protein Kinase Ck2 ◽  
Crystal Packing ◽  
Unit Cell ◽  
Monoclinic Space Group ◽  
X Rays ◽  
Α Subunit ◽  
Cell Parameters ◽  
Packing Parameter ◽  
Kinase Ck2

The catalytic (α) subunit of protein kinase CK2 (CK2α) was originally cloned and overexpressed in the Escherichia coli strain pT7-7/BL21(DE3). The protein has been purified to homogeneity and crystallized. The crystals belong to the monoclinic space group C2, they have unit-cell parameters a = 142.6, b = 61.3, c = 45.6 Å, β = 103.3° and diffract X-rays to at least 2.0 Å resolution. The calculated crystal packing parameter is Vm = 2.47 Å3 Da−1 suggesting that one CK2α molecule is contained in the asymmetric unit and that the solvent content of the unit cell is 50%.

Crystallization and preliminary diffraction studies of a truncated form of a novel protease from spores of Bacillus megaterium

2000 ◽  
Vol 56 (1) ◽  
pp. 70-72 ◽  
Author(s):  
Karthe Ponnuraj ◽  
Stephen Kelly ◽  
Claudio Nessi ◽  
Peter Setlow ◽  
Mark J. Jedrzejas
Keyword(s):  
Synchrotron Radiation ◽  
Bacillus Megaterium ◽  
Diffusion Method ◽  
Monoclinic Space Group ◽  
X Rays ◽  
Unit Cell Parameters ◽  
Truncated Form ◽  
Cell Parameters ◽  
Peg 4000 ◽  
Spore Proteins

During germination of spores of Bacillus species, a novel protease termed GPR initiates the degradation of a group of small acid-soluble spore proteins which protect the dormant spore's DNA from damage. Trypsin digestion of the zymogen of B. megaterium GPR removes ∼15 kDa from the C-terminal end of the 46 kDa zymogen subunit, leaving a 30 kDa subunit. Single crystals of this truncated form of GPR have been obtained by the vapor-diffusion method using PEG 4000 as a precipitating agent. The crystals belong to the monoclinic space group P21, with unit-cell parameters a = 67.99, b = 105.34, c = 108.63 Å, β = 95.68°. The cryofrozen crystals diffract X-rays to about 3.3 Å using synchrotron radiation.

Crystallization and preliminary X-ray diffraction studies of undecaprenyl diphosphate synthase from Micrococcus luteus B-P 26

1999 ◽  
Vol 55 (9) ◽  
pp. 1606-1607 ◽  
Author(s):  
Masahiro Fujihashi ◽  
Naoto Shimizu ◽  
Yuan-Wei Zhang ◽  
Tanetoshi Koyama ◽  
Kunio Miki
Keyword(s):  
Micrococcus Luteus ◽  
Crystal Structure Analysis ◽  
Diffusion Method ◽  
Monoclinic Space Group ◽  
Lithium Sulfate ◽  
X Rays ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters

Undecaprenyl diphosphate synthase from Micrococcus luteus B-P 26, one of the Z-prenyl chain-elongating enzymes, was crystallized using the sitting-drop vapour-diffusion method with ammonium sulfate and lithium sulfate as precipitants. The crystals belong to the monoclinic space group C2, with unit-cell parameters a = 127.2, b = 60.2, c = 75.7 Å, β = 105.6°. The crystals diffract X-rays to at least 2.2 Å resolution using synchrotron radiation and are suitable for high-resolution crystal structure analysis.

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