Energetic materials: α-NTO crystallizes as a four-component triclinic twin

2005 ◽  
Vol 61 (5) ◽  
pp. 577-584 ◽  
Author(s):  
Nadezhda Bolotina ◽  
Kristin Kirschbaum ◽  
A. Alan Pinkerton
Keyword(s):  
Energetic Materials ◽  
Crystal Packing ◽  
Energetic Material ◽  
Data Sets ◽  
Flat Chain ◽  
Planar Molecules ◽  
Triclinic Unit Cell ◽  
Symmetry Space ◽  
Symmetry Space Group ◽  
Additional Hydrogen

The prevalent polymorph of the energetic material 5-nitro-2,4-dihydro-1,2,4,-triazol-3-one, α-NTO, crystallizes as a four-component twin with triclinic symmetry (space group P\bar 1). All crystals under investigation were fourlings, i.e. they contained each of the four possible twin components. Complete data sets were collected for two crystals, one with a predominant amount of one individual component (55%) and one with approximately equal volumes of each component. In both cases the fourling components are related by the twofold axes inherent in the holohedral symmetry of a pseudo-orthorhombic superlattice with a o = a t , b o = b t and c o = a t + b t + 2c t . The triclinic unit cell contains four crystallographically independent planar molecules in the asymmetric unit, each of which forms a hydrogen-bonded flat chain parallel to a t . Pairs of chains are combined into planar ribbons by additional hydrogen bonds. Thus, two independent ribbons extend parallel to a t , creating a dihedral angle of ∼ 70°. The origin of the twinning is derived from consideration of the crystal packing and the hydrogen-bonding scheme.

scholarly journals Photoconductivity of the Single Crystals Pb4Ga4GeS12 and Pb4Ga4GeSe12

Proceedings ◽  
2020 ◽  
Vol 62 (1) ◽  
pp. 4
Author(s):  
Hadj Bellagra ◽  
Oksana Nyhmatullina ◽  
Yuri Kogut ◽  
Halyna Myronchuk ◽  
Lyudmyla Piskach
Keyword(s):  
Ternary Systems ◽  
Semiconductor Materials ◽  
Tetragonal Symmetry ◽  
Bandgap Energy ◽  
Experimental Measurements ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vertical Bridgman ◽  
Symmetry Space ◽  
Symmetry Space Group

Quaternary semiconductor materials of the Pb4Ga4GeS(Se)12 composition have attracted the attention of researchers due to their possible use as active elements of optoelectronics and nonlinear optics. The Pb4Ga4GeS(Se)12 phases belong to the solid solution ranges of the Pb3Ga2GeS(Se)8 compounds which form in the quasi-ternary systems PbS(Se)−Ga2S(Se)3−GeS(Se)2 at the cross of the PbGa2S(Se)4−Pb2GeS(Se)4 and PbS(Se)−PbGa2GeS(Se)6 sections. The quaternary sulfide melts congruently at 943 K. The crystallization of the Pb4Ga4GeSe12 phase is associated with the ternary peritectic process Lp + PbSe ↔ PbGa2S4 + Pb3Ga2GeSe8 at 868 K. For the single crystal studies, Pb4Ga4GeS(Se)12 were pre-synthesized by co-melting high-purity elements. The X-ray diffraction results confirm that these compounds possess non-centrosymmetric crystal structure (tetragonal symmetry, space group P–421c). The crystals were grown by the vertical Bridgman method in a two-zone furnace. The starting composition was stoichiometric for Pb4Ga4GeS12, and the solution-melt method was used for the selenide Pb4Ga4GeSe12. The obtained value of the bandgap energy for the Pb4Ga4GeS12 and Pb4Ga4GeSe12 crystals is 1.86 and 2.28 eV, respectively. Experimental measurements of the spectral distribution of photoconductivity for the Pb4Ga4GeS12 and Pb4Ga4GeSe12 crystals exhibit the presence of two spectral maxima. The first lies in the region of 570 (2.17 eV) and 680 nm (1.82 eV), respectively, and matches the optical bandgap estimates well. The locations of the admixture maxima at about 1030 (1.20 eV) and 1340 nm (0.92 eV), respectively, agree satisfactorily with the calculated energy positions of the defects vs. and VSe.

Introduction of the acylamino group to bridged bis(nitroamino-1,2,4-triazole): a strategy for tuning the sensitivity of energetic materials

2021 ◽  
Vol 45 (38) ◽  
pp. 18059-18064
Author(s):  
Dongxu Chen ◽  
Jiangshan Zhao ◽  
Hongwei Yang ◽  
Hao Gu ◽  
Guangbin Cheng
Keyword(s):  
Energetic Materials ◽  
Energetic Material

Introduction of the acylamino group into energetic material compounds will contribute to balancing the sensitivity and the energy.

scholarly journals Subsolidus solution and ionic conductivity of rock-salt structured Li3+5xTa1−xO4 electroceramics

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
S. Shari ◽  
K.B. Tan ◽  
C.C. Khaw ◽  
Z. Zainal ◽  
O.J. Lee ◽  
...  
Keyword(s):  
Rock Salt ◽  
Xrd Analysis ◽  
Secondary Phases ◽  
Ionic Conductors ◽  
Rock Salt Structure ◽  
Conventional Solid State Reaction ◽  
Salt Structure ◽  
Crystallite Sizes ◽  
Symmetry Space ◽  
Symmetry Space Group

AbstractLithium tantalate solid solution, Li3+5xTa1−xO4 was prepared by conventional solid-state reaction at 925 °C for 48 h. The XRD analysis confirmed that these materials crystallized in a monoclinic symmetry, space group C2/C and Z = 8, which was similar to the reported International Crystal Database (ICDD), No. 98-006-7675. The host structure, β-Li3TaO4 had a rock-salt structure with a cationic order of Li+:Ta5+ = 3:1 over the octahedral sites. A rather narrow subsolidus solution range, i.e. Li3+5xTa1−xO4 (0 ⩽ x ⩽ 0.059) was determined and the formation mechanism was proposed as a replacement of Ta5+ by excessive Li+, i.e. Ta5+ ↔ 5Li+. Both Scherrer and Williamson-Hall (W-H) methods indicated the average crystallite sizes in the range of 31 nm to 51 nm. Two secondary phases, Li4TaO4:5 and LiTaO3 were observed at x = 0.070 and x = −0:013, respectively. These materials were moderate lithium ionic conductors with the highest conductivity of ~2.5 × 10−3 Ω 1 ˙cm−1 at x = 0, at 0 °C and 850 °C; the activation energies were found in the range of 0.63 eV to 0.68 eV.

scholarly journals Zur Kenntnis eines Barium-Oxoniobat-Tellurats: Ba2Nb2TeO10 / On a Barium-Oxoniobate-Tellurate: Ba2Nb2TeO10

1996 ◽  
Vol 51 (10) ◽  
pp. 1407-1410 ◽  
Author(s):  
B. Wedel ◽  
Hk. Müller-Buschbaum
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Single Crystals ◽  
Solid State Reactions ◽  
Orthorhombic Symmetry ◽  
X Ray ◽  
Lattice Constants ◽  
Group D ◽  
Symmetry Space ◽  
Symmetry Space Group

Single crystals of Ba2Nb2TeO10) have been prepared by solid state reactions in air. X-ray investigations led to orthorhombic symmetry, space group D152h-Pbca, a = 7.242(4), b = 12.433(3), c = 9.932(3) Å. Z = 4. Nb5+ and Te6+ show octahedral coordination by O2- . The crystal structure is characterized by planes of edge- and corner-sharing NbO6- and TeO6octahedra. It is shown that in spite of nearly identical lattice constants of Ba2Nb2TeO10 with compounds of the composition M0,5BaNbTe2O9 the so far unknown crystals of these substances may not be derived from the Ba2Nb2TeO10 type.

Synthese und Röntgenstrukturanalyse von KCuGd2Mo4O16 und KCuTb2Mo4O16/Synthesis and X-Ray Analysis of KCuGd2Mo4O16 and KCuTb2Mo4O16

1995 ◽  
Vol 50 (12) ◽  
pp. 1794-1798 ◽  
Author(s):  
Hk. Müller-Buschbaum ◽  
St. Gallinat
Keyword(s):  
Lattice Energy ◽  
Rare Earth Ions ◽  
Monoclinic Symmetry ◽  
X Ray ◽  
Coulomb Term ◽  
Relationship Of ◽  
The Relationship ◽  
Symmetry Space ◽  
Oxidation State Of Copper ◽  
Symmetry Space Group

Single crystals of the so far unknown compounds KCuGd2Mo4O16 (I) and KCuTb2Mo4O16 (II) have been prepared by flux technique. The compounds crystallize with monoclinic symmetry. space group C62h-C2 /c with (I): a = 5.278(2), b = 12.666(5), c = 19.604(14) Å; β = 92.76(6)°; (II): a = 5.259(13), b = 12.616(3), c = 19.556(9) Å, β = 92.93(4)°, Z = 4. Molybdenum exhibits tetrahedral coordination. The surroundings of copper can be described by distorted tetrahedra, capped by two more distant oxygen atoms, and the rare earth ions show a square antiprism. Potassium is inside an irregular polyhedron. The relationship of the structures of (I) and (II) is discussed with respect to the KLnMo2O8 type compounds. Coulomb term calculations of the lattice energy indicate an oxidation state of copper higher than CuI.

Eine synthetische Spezies zum Mineral Howardevansit mit Eisen anstelle von Kupfer: NaFe3V3O12 / A Synthetic Species of the Mineral Howardevansite with Copper Displacing Iron: NaFe3V3O12

1995 ◽  
Vol 50 (1) ◽  
pp. 51-55 ◽  
Author(s):  
F.-D. Martin ◽  
Hk. Müller-Buschbaum
Keyword(s):  
Solid State ◽  
Melting Point ◽  
Single Crystals ◽  
Crystal Chemistry ◽  
Solid State Reaction ◽  
Space Group ◽  
Triclinic Symmetry ◽  
Symmetry Space ◽  
Symmetry Space Group

Single crystals of NaFe3V3O12 have been prepared by solid state reaction below the melting point of the reaction mixture. This compound is isotypic to the mineral Howardevansite but shows lower triclinic symmetry, space group C11–P1, a = 6.757(2), b = 8.155(2), c = 9.816(3) Å, α = 106.05(2), β = 104.401(9), γ = 102.09(2)°, Z = 2. The acentric space group is caused by the sodium positions, all other atoms comply with the space group P̄ of Howardevansite. The different ions are coordinated by O2- forming VO4 tetrahedra, FeO6 octahedra, trigonal FeO5 bipyramids and irregular NaO5 and NaO7 polyhedra, respectively. The crystal chemistry is discussed with respect to Howardevansite.

Achieving tunable chemical reactivity through photo-initiation of energetic materials at metal oxide surfaces

2020 ◽  
Vol 22 (43) ◽  
pp. 25284-25296
Author(s):  
Maija M. Kuklja ◽  
Roman Tsyshevsky ◽  
Anton S. Zverev ◽  
Anatoly Mitrofanov ◽  
Natalya Ilyakova ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Chemical Reactions ◽  
Energetic Materials ◽  
Chemical Reactivity ◽  
Energetic Material ◽  
Oxide Surfaces ◽  
Oxide Interfaces ◽  
Metal Oxide Surfaces

Photo-stimulated chemical reactions in energetic materials can be highly controlled by selectively designing energetic material – metal oxide interfaces with tailored properties.

Gemischtvalente Oxovanadate, I Ein neuer Strukturtyp für die Verbindung BaV10O15/Oxovanadates with Mixed Valence, I A New Crystal Structure of BaV10O15

1980 ◽  
Vol 35 (6) ◽  
pp. 669-671 ◽  
Author(s):  
D. Chales de Beaulieu ◽  
Hk. Müller-Buschbaum
Keyword(s):  
Crystal Structure ◽  
Mixed Valence ◽  
Structure Type ◽  
Orthorhombic Symmetry ◽  
Temperature Reaction ◽  
X Ray ◽  
High Temperature Reaction ◽  
Group D ◽  
Symmetry Space ◽  
Symmetry Space Group

Abstract BaV10O15 was prepared by high temperature reaction of BaO and V2O3 in H2-atmosphere (T > 1800°). X-ray investigations of single crystals show a new structure type with octa-hedral coordination of V3+/V2+ (statistical distribution) and cuboctahedral surrounding of Ba2+ . Orthorhombic symmetry, space group D182h-Ccmb, a = 995,8; b = 1161,8; c = 941,0; Z = 4.

Über ein cadmiumreiches Orthovanadat Ba2,5Cd11(VO4)9 mit Cadmium in oktaedrischer und tetragonal pyramidaler Koordination / On a Cadmium Rich Orthovanadate Ba2,5Cd11(VO4)9 Showing Cadmium in Octahedral and Square Pyramidal Coordination

1997 ◽  
Vol 52 (8) ◽  
pp. 989-993 ◽  
Author(s):  
B Mertens ◽  
Hk Müller-Buschbaum
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Single Crystals ◽  
Three Dimensional ◽  
Lattice Energy ◽  
Solid State Reactions ◽  
Orthorhombic Symmetry ◽  
Group D ◽  
Symmetry Space ◽  
Symmetry Space Group

Single crystals of Ba2,5Cd11(VO4)9 have been prepared by solid state reactions. The new compound crystallizes with orthorhombic symmetry, space group D142h-Pbcn, a = 20.842(6), b = 13.471(3), c = 11.838(9) Å, Z = 4. The crystal structure is characterized and dominated by CdO6 octahedra and unusual square pyramids of O2- around Cd2+ forming a three-dimensional [Cd11O36] network. The interstices are occupied by V5+ and Ba2+ ions. This results in VO4 tetrahedra and irregular BaO10 polyhedra isolated from each other. Occupation of the barium positions is deficient in agreement with the valence state V5+ and calculations of the coulomb terms of lattice energy.

Synthese und Struktureines Strontium-Vanadyl-Phosphats: Sr2(VO)(PO4)2 / Synthesis and Structure of a Strontium Vanadyl Phosphate: Sr2(VO)(PO4)2

1996 ◽  
Vol 51 (7) ◽  
pp. 929-933 ◽  
Author(s):  
C. Wadewitz ◽  
Hk. Müller-Buschbaum
Keyword(s):  
Solid State ◽  
Solid State Reactions ◽  
Vanadyl Phosphate ◽  
Monoclinic Symmetry ◽  
X Ray ◽  
Vanadyl Group ◽  
Dark Green ◽  
Symmetry Space ◽  
Oxygen Distance ◽  
Symmetry Space Group

Dark green single crystals of Sr2(VO)P2O8 have been prepared by solid state reactions in closed quartz tubes. X-ray investigations led to monoclinic symmetry, space group C2h6-I2/a, a = 6.744(4), b = 15.866(4), c = 7.032(2) Å, β = 115.41(2), Z = 4. Sr2(VO)P2O8 is isotypic to Sr2(VO)V2O8 and shows V4+ in split positions. The split positions are in non-centric octahedral coordination forming a short vanadium to oxygen distance typical for the vanadyl group. The crystal chemistry of the monovanadyl orthophate Sr2(VO)P2O8 is discussed considering related divanadyl phosphates.

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