scholarly journals The Forgotten Polymorphism of Hydrazine Sulfate: Crystal Structure of the Metastable Monoclinic Form II

2017 ◽  
Vol 643 (23) ◽  
pp. 2019-2023 ◽  
Author(s):  
Thomas Martin ◽  
Juliane Fleissner ◽  
Wolfgang Milius ◽  
Josef Breu
Keyword(s):  
Crystal Structure ◽  
Hydrazine Sulfate ◽  
Monoclinic Form ◽  
Sulfate Crystal

Crystal structure of the monoclinic form of (C6H5)3PO

1973 ◽  
Vol 14 (1) ◽  
pp. 101-108 ◽  
Author(s):  
A. I. Gusev ◽  
N. G. Bokii ◽  
N. N. Afonina ◽  
T. V. Timofeeva ◽  
A. E. Kalinin ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Monoclinic Form

Crystal structure of the monoclinic form of bis-dimethylamide 2-methylbuta-1,3-dienethiophosphone acid

1990 ◽  
Vol 31 (2) ◽  
pp. 369-371
Author(s):  
Yu. É. Ovchinnikov ◽  
V. E. Shklover ◽  
Yu. T. Struchkov
Keyword(s):  
Crystal Structure ◽  
Monoclinic Form

NTO Polymorphs

1992 ◽  
Vol 296 ◽  
Author(s):  
Kien-yin Lee ◽  
Richard Giloxdi
Keyword(s):  
Crystal Structure ◽  
Cell Density ◽  
Unit Cell ◽  
Monoclinic Space Group ◽  
Triclinic Space Group ◽  
Space Group ◽  
Monoclinic Form ◽  
Network Of Hydrogen Bonds ◽  
Air Bag ◽  
Ray Methods

AbstractNTO is an explosive of current interest. It has been evaluated as an insensitive component to replace RDX in the bomb fill, and as a major ingredient for the auto air bag system. The crystal structure of the β from of NTO has been determined by single-crystal X-ray methods. The unit cell is monoclinic, space group P21/c, with a = 9.326, b = 5.515, c = 9.107 Å, β = 100.77°. There are four molecules in the cell, density 1.878 g/cm3. Infinite extension of H-bonding in two-dimensional sheets occurs in the monoclinic form. Bond lengths and angles all have normal values.Efforts have been made to determine the crystal structure of α-NTO. However, a structure refined only to R = 17% was obtained, probably due to some kind of twinning about the crystal needle axis. The unit cell is triclinic, space group P1, with a = 5.12, b = 10.30, c = 17.9 Å, α = 106.7°, β= 97.7°, γ = 90.2°. There are eight molecules in the cell, density 1.92 g/cm3. Ribbons of NTO molecules formed by a relatively strong network of hydrogen bonds are observed. It was found that α-NTO is the stable, dominating form. A variety of techniques have been chosen to identify the two polymorphs.

Natural occurrence of monoclinic Fe3S4 nano-precipitates in pyrrhotite from the Sudbury ore deposit: a Z-contrast imaging and density functional theory study

2015 ◽  
Vol 79 (2) ◽  
pp. 377-385 ◽  
Author(s):  
Huifang Xu ◽  
Zhizhang Shen ◽  
Hiromi Konishi
Keyword(s):  
Crystal Structure ◽  
Density Functional Theory ◽  
Density Functional ◽  
Natural Occurrence ◽  
Contrast Imaging ◽  
Functional Theory ◽  
Ore Deposit ◽  
Monoclinic Form ◽  
Nano Crystal ◽  
Z Contrast

AbstractA monoclinic form of Fe3S4, a polymorph of cubic greigite, occurs as precipitates in a sample of pyrrhotite collected from the Sudbury ore deposit. The nano-crystal precipitates are in a topotaxial relationship with the host pyrrhotite-4C (Fe7S8). The precipitate and the host pyrrhotite have a coherent (001) interface. Half of the octahedral layers in the crystal structure are fully occupied by Fe, while the other half of the octahedral layers are occupied by Fe atoms and vacancies in an ordered manner along the a axis. The crystal structure of the Fe3S4 nano-precipitates has monoclinic symmetry with a space group of I2/m. Its c dimension is 6% smaller than that of the host pyrrhotite due to the large number of vacancies in the structure. Fractional coordinates for S and Fe atoms within the unit cell are determined from Z-contrast images and density functional theory (DFT). The calculated results match the measured values very well. It is proposed that the monoclinic Fe3S4 nano-precipitates formed through ordering of vacancies in pyrrhotite with a low Fe/S ratio (i.e. <0.875) at low temperature.

scholarly journals Crystal Structure of a Monoclinic Form of Naphthazarirn

1957 ◽  
Vol 30 (5) ◽  
pp. 532-536 ◽  
Author(s):  
Hideo Watase ◽  
Kenji Osaki ◽  
Isamu Nitta
Keyword(s):  
Crystal Structure ◽  
Monoclinic Form

scholarly journals Crystal Structure of an Unstable Monoclinic Form of Dinitrogen Tetroxide.

1963 ◽  
Vol 17 ◽  
pp. 2419-2422 ◽  
Author(s):  
P. Groth ◽  
L. S. Hersh ◽  
J. M. Toguri ◽  
Kenneth Hedberg ◽  
M. Trætteberg
Keyword(s):  
Crystal Structure ◽  
Monoclinic Form ◽  
Dinitrogen Tetroxide

scholarly journals A triclinic polymorph of dicadmium divanadate(V)

2013 ◽  
Vol 69 (11) ◽  
pp. i79-i79 ◽  
Author(s):  
Ahmed Ould Saleck ◽  
Abderrazzak Assani ◽  
Mohamed Saadi ◽  
Lahcen El Ammari
Keyword(s):  
Crystal Structure ◽  
Title Compound ◽  
Three Dimensional ◽  
Framework Structure ◽  
Hydrothermal Conditions ◽  
Coordination Environment ◽  
Coordination Numbers ◽  
Monoclinic Form ◽  
Triclinic Symmetry

The title compound, Cd2V2O7, was obtained under hydrothermal conditions. Different from the known monoclinic form, the new polymorph of Cd2V2O7has triclinic symmetry and is isotypic with Ca2V2O7. The building units of the crystal structure are two Cd2+cations, with coordination numbers of six and seven, and two V atoms with a tetrahedral and a significantly distorted trigonal–pyramidal coordination environment, respectively. Two VO5pyramids share an edge and each pyramid is connected to one VO4tetrahedronviaa corner atom, forming an isolated V4O148−anion. These anions are arranged in sheets parallel to (-211) and are linked through the Cd2+cations into a three-dimensional framework structure.

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