Rotation von Anionpolyedern in kubischen Kristallgittern. I. Die Perchlorate

Finbak, Chr.; Hassel, O.

doi:10.1515/zpch-1936-3212

Cited by 14 publications

(5 citation statements)

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“…In a later paper331 the method was adapted to elevated pressures, and values in the range ~530-620°were obtained in the pressure range [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] atm; the general trend indicated an increase in surface temperature with pressure. More recently Fowling63 has correlated considerable data on the dependence of surface temperature on burning rate.…”

Section: Surface Temperaturementioning

confidence: 99%

“…Large portions of the surface of the quenched samples were covered by a frothy-looking layer. The hollow bubbles in the frothy layers had AP walls of thickness [2][3][4] Atm. These observations provide convincing testimony for the presence of a surface melt.…”

Section: Surface Temperaturementioning

confidence: 99%

“…The specific heat of AP is 0.309 cal g-1 deg-1 between 15 and 240°and 0.365 cal g-1 deg-1 above the transition point.17 Rosser, Inami, and Wise18 have measured the thermal diffusivity of AP samples of porosity 0.023, sample density 1.90 g/cm8, and particle size 43-61 µ . In the temperature range 50-240°, the thermal diffusivity is a linear function of temperature and can be expressed by the equation = 3.59 X 10-8 -(4.40 X 10-6)7 cm2/sec (1) where 7 is the temperature in °K.…”

Section: Introductionmentioning

confidence: 99%

“…3, 135 (1966). (324) L. H. Caveny and C. U. Pittman, "Contribution of Solid Phase Heat Release to Ammonium Perchlorate Composite Propellant Burning Rate," to be published.325) R. Friedman, AIAA J., 5, 1217 (1967).ture…”

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confidence: 99%

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Decomposition and combustion of ammonium perchlorate

Jacobs¹,

Whitehead²

1969

Chem. Rev.

451

181

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Section: Surface Temperaturementioning

confidence: 99%

Section: Surface Temperaturementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Decomposition and combustion of ammonium perchlorate

Jacobs¹,

Whitehead²

1969

Chem. Rev.

451

181

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“…The complex reorientational dynamics of both the anions and cations as well as the possible phase transitions have been the major points of interest. It is well established that NH 4 ClO 4 undergoes a reversible crystallographic transition at 513 K from a high-temperature cubic structure to an orthorhombic structure which is then maintained down to room temperature [2]. The orthorhombic unit cell belongs to the space group P nma with Z = 4.…”

Section: Introductionmentioning

confidence: 99%

An electron spin-resonance study of radicals in single crystals

Hegde

Rastogi

Damle

et al. 1997

J. Phys.: Condens. Matter

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An ESR study of centres in x-irradiated ammonium perchlorate single crystals is carried out that is aimed at resolving the controversy that has recently arisen over the possible occurrence of low-temperature phase transitions in the compound (room temperature structure: orthorhombic; space group Pnma). The ESR spectra are recorded as a function of the orientation of the magnetic field H in the three orthogonal crystallographic planes at 300 K, 77 K, and 4.2 K, and also as a function of temperature for H parallel to the principal z-component of the hyperfine coupling tensor. The analysis of the spectra shows that while the -tensor remained axial over the entire temperature range 2.0052(3), 2.0055(3), 2.0057(3) and 2.0090(3), 2.0096(3), 2.0105(3) at 300 K, 77 K, and 4.2 K respectively), , which is rhombic at room temperature , , and at 300 K) becomes more axial as the temperature is lowered , , and at 77 K, and , , and at 4.2 K). No changes in the spectra attributable to any phase transition were observed, and we conclude that does not undergo any phase transition below room temperature. Furthermore, it is found that during radiative decomposition the mirror-related Cl - O bonds, even though weaker than the other Cl - O bonds, do not break, thus confirming our earlier conclusion that mirror symmetry is preserved during radiation damage.

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Orientierungsfehlordnung komplexer Kationen und Anionen in Hochtemperaturphasen von Ionenverbindungen ‐ Ergebnisse dreidimensionaler Elektronendichteberechnungen aufgrund von Röntgendaten

Berthold

Bäthge

Hölscher

et al. 1983

Ber Bunsenges Phys Chem

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The crystal structures of the orientationally disordered cubic high‐temperature phases of NaClO4, RbClO4, CsClO4, AgClO4, and Co(C5H5)2ClO4 have been investigated using single crystal X‐ray diffraction data. In the case of NaClO4 and AgClO4 the ClO4‐tetrahedra occupy 6 orientations, characterized by the fact that in each orientation only one of the three 4‐axes of the tetrahedra lies parallel to the cubic crystal axes. In RbClO4 and CsClO4 the orientational disorder comprises 2 orientations of the ClO4‐tetrahedra. In both of them all three 4‐axes simultaneously point into the directions of the cubic crystal axes. The space group in all cases is Fm3m, Z = 4. Co(C5H5)2ClO4 transforms at 376 K from the tetragonal room‐temperature structure (space group 14/mcm, Z = 16) into a primitive cubic structure (space group Pm3m, Z = 1), in which the sandwich‐like Co(C5H5) 2+‐cations and the ClO 4−‐anions are orientationally disordered. The electron density distribution around the Co‐atom proves that the cations occupy statistically three different orientations with the fivefold axis parallel to the x‐, y‐ or z‐direction. The electron density distribution around the chlorine atom reveals 6 maxima forming an octahedron and can be interpreted, if one assumes orientations of the ClO4‐tetrahedra with one of their threefold axes lying parallel or approximately parallel to the cubic crystal axes. The three oxygen atoms, which are not situated on the threefold axis, are rotationally disordered and hence in the electron density map not resolved. In NOCIO4 at 150 K the NO+‐cations have orientations perpendicular to the mirror planes of the space group Pnma. However, a disorder with respect to the direction of the NO+‐cations (NO or ON) is probable. At 298 K the cations are orientationally disordered. While approximately 60% of the NO+‐cations still have orientations perpendicular to the mirror planes, about 40% have orientations with both nitrogen and oxygen lying in the mirror planes.

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Rotation von Anionpolyedern in kubischen Kristallgittern. I. Die Perchlorate

Cited by 14 publications

References 0 publications

Decomposition and combustion of ammonium perchlorate

Decomposition and combustion of ammonium perchlorate

An electron spin-resonance study of radicals in single crystals

Orientierungsfehlordnung komplexer Kationen und Anionen in Hochtemperaturphasen von Ionenverbindungen ‐ Ergebnisse dreidimensionaler Elektronendichteberechnungen aufgrund von Röntgendaten

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