Structure of Magnesium Hydroxide Sulfate [2MgSO4.Mg(OH)2] and Solid Solution in Magnesium Hydroxide Sulfate Hydrate and Caminite

1997 ◽  
Vol 53 (3) ◽  
pp. 358-363 ◽  
Author(s):  
M. E. Fleet ◽  
S. W. Knipe
Keyword(s):  
Solid Solution ◽  
Single Crystal ◽  
Magnesium Hydroxide ◽  
Substitution Reaction ◽  
Ocean Floor ◽  
Octahedral Position ◽  
X Ray ◽  
Sulfate Hydrate ◽  
Gold Bearing ◽  
Magnesium Hydroxide Sulfate Hydrate

Magnesium hydroxide sulfate [2MgSO4.Mg(OH)2; MHS] is tetragonal with a = 7.454 (1), c = 12.885 (2) Å, V = 716.0 Å3, space group P43212, Z = 4 and D x 2.774 g cm−3. The structure (single-crystal X-ray, R = 0.025, wR = 0.023) comprises spiral (43) single chains of corner-shared Mg(2) octahedra cross-linked by SO4 tetrahedra and face-shared Mg(1) octahedra. A linear ternary group of face-shared Mg octahedra [Mg(2)—Mg(1)—Mg(2)] alternates with an unoccupied octahedral position in rows along [\overline 110]. A crystal of MHS was grown hydrothermally (0.15 GPa, 673 K) from gold-bearing Mg—S—O—H fluid. The MHS structure, with Mg(1) octahedra sharing two octahedral faces with Mg(2) octahedra, revises the structure assumed for the complex solid solution magnesium hydroxide sulfate hydrate and the related ocean-floor mineral caminite [2MgSO4.xMg(OH)2.(2 − 2x)H2O; 0.5 < x < 1.0]. The substitution reaction appears to be Mg(1)2+ ⇋ 2H+. The H-substituted MHS structure is distinguished from that of kieserite (MgSO4.H2O), which has straight single chains of corner-shared Mg octahedra.

Hydrothermal Synthesis of Magnesium Hydroxide Sulfate Hydrate Whisker Flame Retardant

2012 ◽  
Vol 174-177 ◽  
pp. 1034-1037
Author(s):  
Jun Ji Zhang ◽  
Bin Wu ◽  
Shuang Tao ◽  
Xiao Man Yuan ◽  
Qiong Zhang ◽  
...  
Keyword(s):  
Phase Composition ◽  
Reaction Time ◽  
Hydrothermal Synthesis ◽  
Magnesium Hydroxide ◽  
Volume Ratio ◽  
Mixed Solution ◽  
Sem Images ◽  
X Ray ◽  
Sulfate Hydrate ◽  
Magnesium Hydroxide Sulfate Hydrate

Magnesium Hydroxide Sulfate Hydrate (MgSO4•5Mg(OH)2•3H2O, MHSH) whiskers were synthesized via the hydrothermal method in a mixed solution of magnesium sulfate (MS) and NH3•H2O . X-ray powder diffraction (XRD) investigations showed that the phase composition changed from Mg(OH)2 to MHSH as the volume ratio of MS / NH3•H2O increasing gradually. Accordingly, SEM images showed that the morphological structures changed from granule dominant to whisker dominant. The morphology of the samples changed from lathy to whisker gradually as the reaction time increasing under the same volume ratio of MS / NH3•H2O and reaction temperature of 180 °C.

One-Step Hydrothermal Synthesis of Magnesium Hydroxide Sulfate Hydrate Whiskers Using Brine as Raw Material

2011 ◽  
Vol 233-235 ◽  
pp. 2545-2548 ◽  
Author(s):  
Dong Yang Li ◽  
Xian Guo Li ◽  
Li Juan Feng ◽  
Chuan Hui Gao
Keyword(s):  
Magnesium Hydroxide ◽  
Raw Materials ◽  
Hydrothermal Process ◽  
Raw Material ◽  
X Ray ◽  
One Step ◽  
Utilization Ratio ◽  
Sulfate Hydrate ◽  
Scanning Electron ◽  
Magnesium Hydroxide Sulfate Hydrate

Magnesium hydroxide sulfate hydrate (MHSH) whiskers were prepared using brine, sodium hydroxide and sodium sulfate as raw materials by one-step hydrothermal process. X-ray powder diffraction (XRD), thermal analysis (TG-DTG) and scanning electron microscope (SEM) were employed to characterize the MHSH whiskers. It was shown that the MHSH whiskers were MgSO4•5Mg(OH)2 •2H2O with a diameter of 0.2–0.3 μm and a length of 20–30 μm . The thermal decomposition of MHSH whisker was demonstrated a three-step scheme based on the TG-DTG data. The utilization ratio of magnesium in brine was above 80%.

Crystal chemistry of lamprophyllite-group minerals from the Murun alkaline complex (Russia) and pegmatites of Rocky Boy and Gordon Butte (USA): single crystal X-ray diffraction and Raman spectroscopy study

2021 ◽  
Vol 77 (2) ◽  
Author(s):  
Sergey M. Aksenov ◽  
Anastasia D. Ryanskaya ◽  
Yuliya V. Shchapova ◽  
Nikita V. Chukanov ◽  
Nikolay V. Vladykin ◽  
...  
Keyword(s):  
Solid Solution ◽  
Single Crystal ◽  
Raman Spectra ◽  
Crystal Chemistry ◽  
Solid Solution Series ◽  
X Ray Diffraction ◽  
Alkaline Complex ◽  
Oh Groups ◽  
X Ray ◽  
Solution Series

Specific features of the crystal chemistry of lamprophyllite-group minerals (LGMs) are discussed using the available literature data and the results of the single-crystal X-ray diffraction and a Raman spectroscopic studies of several samples taken from the Murun alkaline complex (Russia), and Rocky Boy and Gordon Butte pegmatites (USA) presented here. The studied samples are unique in their chemical features and the distribution of cations over structural sites. In particular, the sample from the Gordon Butte pegmatite is a member of the barytolamprophyllite–emmerichite solid solution series, whereas the samples from the Murun alkaline complex and from the Rocky Boy pegmatite are intermediate members of the solid solution series formed by lamprophyllite and a hypothetical Sr analogue of emmerichite. The predominance of O2− over OH− and F− at the X site is a specific feature of sample Cha-192 from the Murun alkaline complex. New data on the Raman spectra of LGMs obtained in this work show that the wavenumbers of the O—H stretching vibrations depend on the occupancies of the M2 and M3 sites coordinating with (OH)− groups. Cations other than Na+ and Ti4+ (mainly, Mg and Fe3+) can play a significant role in the coordination of the X site occupied by (OH)−. Data on polarized Raman spectra of an oriented sample indicate that the OH groups having different local coordinations have similar orientations with respect to the crystal. The calculated measures of similarity (Δ) for lamprophyllite and ericssonite are identical (0.157 and 0.077 for the 2M- and 2O-polytypes, respectively), which indicates that these minerals are crystal-chemically isotypic and probably should be considered within the same mineral group by analogy to the other mineralogical groups which combine isotypic minerals.

Thermal and X-Ray Diffraction Studies of Doped and Undoped Single Crystal and Polycrystalline BaTiO3

1994 ◽  
Vol 360 ◽  
Author(s):  
L.G. Carreiro ◽  
J.V. Marzik ◽  
K.K Deb
Keyword(s):  
Solid Solution ◽  
Curie Temperature ◽  
Single Crystal ◽  
Dopant Concentration ◽  
Infrared Detection ◽  
Thermal Transition ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Mole Percent ◽  
X Ray

AbstractCalorimetric changes in a series of pure and doped single crystal and polycrystalline BaTiO3 were studied using differential scanning calorimetry over the temperature range of-110°C to 200°BC. The dopants, oxides of niobium and iron were varied from 0.5 to 8 mole percent, and strontium was varied from 5 to 35 mole percent. Endotherms were observed corresponding to three crystallographic transitions. The highest observed thermal transition corresponds to a tetragonal to cubic crystallographic transition and is also associated with the Curie temperature in these materals. Two additional endothermic transitions were also observed, an intermediatetemperature orthorhombic to tetragonal transition, and a low-temperature rhombohedral to orthorhombic transition. The three dopants decreased the crystallographic transition temperatures and Curie temperature as the dopant concentration was increased. X-ray diffraction was used to identify phases present and to determine the extent of solid solution. It is expected that these materials will display improved infrared detection as well as opto-electronic properties.

Superstructured magnesium hydroxide sulfate hydrate fibres

2001 ◽  
Vol 3 (2) ◽  
pp. 151-156 ◽  
Author(s):  
Yi Ding ◽  
Huazhang Zhao ◽  
Yugang Sun ◽  
Guangtao Zhang ◽  
Hao Wu ◽  
...  
Keyword(s):  
Magnesium Hydroxide ◽  
Sulfate Hydrate ◽  
Magnesium Hydroxide Sulfate Hydrate

The solid solution between platinum and palladium in nature

2013 ◽  
Vol 77 (3) ◽  
pp. 269-274 ◽  
Author(s):  
L. Bindi ◽  
F. Zaccarini ◽  
G. Garuti ◽  
N. Angeli
Keyword(s):  
Solid Solution ◽  
Single Crystal ◽  
Structural Data ◽  
Micro Hardness ◽  
Metallic Elements ◽  
X Ray Diffraction ◽  
X Ray ◽  
Complete Solid Solution ◽  
Hardness Values ◽  
Palladium Platinum

AbstractChemical and structural data are reported for platinum–palladium intermediates from two nuggets found at Córrego Bom Sucesso, Minas Gerais, Brazil. Three grains with simple stoichiometries (i.e. PtxPd1−x with x ∼0.67, ∼0.5 and ∼0.33, which correspond to Pt2Pd, PtPd and PtPd2, respectively) were characterized by single-crystal X-ray diffraction and electron-probe microanalysis. In the absence of single-crystal data it might be tempting to hypothesize that such simple stoichiometries represent distinct mineral species, however structural analyses show that all of the phases are cubic and crystallize in space group Fmm. They are, therefore, natural intermediates in the palladium–platinum solid solution. Reflectance and micro-hardness values are reported for the samples and a comparison with the pure metallic elements made. On the basis of information gained from the chemical and structural characterization it can be concluded that there is a complete solid solution between Pt and Pd in nature. These findings corroborate results from experiments on synthetic compounds.

Sign in / Sign up

Export Citation Format

Share Document