5.2.2.8 Tetragonal system: Classes 4 (C{4}), (-4) (S{4}), 4/m (C{4h})

2005 ◽  
pp. 69-70
Author(s):  
K. Vedam
Keyword(s):  
Tetragonal System

Electronic polarizabilities of ions in uniaxial crystals. II. Tetragonal system

1973 ◽  
Vol 34 (8-9) ◽  
pp. 733-739 ◽  
Author(s):  
E. Uzan ◽  
V. Chandrasekharan
Keyword(s):  
Tetragonal System

Über Oxidpnictide: Zur Kenntnis von A2Mn3B2O2 mit A = Sr, Ba und B = As, Sb, Bi / On Oxidpnictides: Preparation and Crystal Structure of A2Mn3B2O2 with A = Sr, Ba and B = As, Sb, Bi

1979 ◽  
Vol 34 (6) ◽  
pp. 777-780 ◽  
Author(s):  
Erwin Brechtel ◽  
Gerhard Cordier ◽  
Herbert Schäfer
Keyword(s):  
Crystal Structure ◽  
Double Layers ◽  
Two Dimensional ◽  
Tetragonal System

Five new oxidpnictides have been prepared and structurally characterized. They crystallize in the tetragonal system, I4/mmm, with the following constants: Sr2Mn3As2O2: a = 416 ± 1 pm, c = 1884 ± 4 pm, c/a = 4.529, Ba2Mn3As2O2 : a = 424.8 ± 0 5 pm, c = 1977 ± 3 pm, c/a = 4.654, Sr2Mn3Sb2O2 : a = 426.2 ± 0.4 pm, c = 2011 ± 2 pm, c/a = 4.718, Ba2Mn3Sb2O2 : a = 436.7 ± 0.5 pm, c = 2078 ± 2 pm, c/a = 4.758, Sr2Mn3Bi2O2 : a = 428 ± 1 pm, c = 2055 ± 5 pm, c/a = 4.801. Mn- and As(Sb,Bi) atoms form tetragonal pyramids, connected by common edges in the basis to two-dimensional sheets. These sheets are separated by double layers of Sr atoms, in which Mn and O atoms are located forming MnO4 square plane nets.

Spinodal Decomposition in the Tetragonal System

1969 ◽  
Vol 32 (2) ◽  
pp. K117-K119 ◽  
Author(s):  
A. H. Schultz ◽  
W. R. Bitler ◽  
V. S. Stubican
Keyword(s):  
Spinodal Decomposition ◽  
Tetragonal System

Synthesis and structure of the ternary nitride Li6WN4

2005 ◽  
Vol 20 (1) ◽  
pp. 18-21 ◽  
Author(s):  
W. X. Yuan ◽  
J. W. Hu ◽  
Y. T. Song ◽  
W. J. Wang ◽  
Y. P. Xu
Keyword(s):  
Crystal Structure ◽  
Thermal Stability ◽  
Room Temperature ◽  
Powder Diffraction Data ◽  
High Quality ◽  
X Ray ◽  
Cell Parameters ◽  
Tetragonal System ◽  
Ternary Nitride ◽  
Stability Measurements

The ternary nitridotungstate Li6WN4 has been synthesized via the solid state reaction of lithium subnitride, Li3N, with W under nitrogen. High quality X-ray powder diffraction data were collected for the crystal-structure determination. Li6WN4 crystallizes in the tetragonal system, space group P42∕nmc, with cell parameters a=6.6759(3) Å and c=4.9280(3) Å, Z=2. Preliminary thermal stability measurements of Li6WN4 show that it is sensitive to moisture, even at room temperature, and decomposes at high temperatures below 1000 °C under flowing nitrogen.

Structure of TlSr2PrCu207−x by Rietveld analysis

1994 ◽  
Vol 9 (3) ◽  
pp. 194-199
Author(s):  
Hoong-Kun Fun ◽  
Ping Yang ◽  
Rusli Othman ◽  
Tsong-Jen Lee ◽  
Chiou-Chu Lai ◽  
...  
Keyword(s):  
Low Temperature ◽  
Crystalline Structure ◽  
Powder Diffraction ◽  
Room Temperature ◽  
Goodness Of Fit ◽  
Rietveld Analysis ◽  
Crystal Data ◽  
X Ray ◽  
Tetragonal System

The crystalline structure of new TlSr2PrCu207−x was obtained at room temperature (300 K) and low temperature (100 K) from X-ray powder diffraction with CuKα radiation using Rietveld analysis. TlSr2PrCu207−x has an isotypical structure with TlBa2CaCu207 (1212). At 300 K, crystal data: Tl0.864Sr2PrCu2O6.75, Mr=727.811, the tetragonal system, P4/mmm, a =3.85404(5) Å, c = 12.1046(2) Å, V=179.80 Å3, Z=1, Dx =6.7218 g cm−3, μ =1143.922 cm−1 (λ = 1.54051 Å), F(000)=317.0, the structure was refined with 28 parameters to Rwp=5.29%, Rp = 3.65% for 3551 step intensities and Rb=7.40%, Rf=639% for 155 peaks, “goodness of fit” 5=3.05. At 100 K, crystal data: Tl0.858Sr2PrCu2O6.61, Mr=724.345, the tetragonal system, P4/mmm, a =3.84872(6) Å, c = 12.0771(3) Å, V=178.89 Å3, Z=1, Dx=6.7235 g cm−3, μ=1146.939 cm−1 (λ= 1.54051 Å), F(000) = 315.4, the structure was refined with 26 parameters to Rwp=6.70%, Rp=5.11% for 2926 step intensities and Rb=7.83%, Rf=6.70% for 131 peaks, “goodness of fit” S = 1.75.

HIGH PRESSURE SYNTHESIS AND STRUCTURAL STUDIES ON (Ca0.3Sr0.7)0.9Cu1-xZnxO2 (0≤ x ≤0.3)

1999 ◽  
Vol 13 (03n04) ◽  
pp. 119-124
Author(s):  
C. VENKATESWARAN ◽  
K. ANBUKUMARAN ◽  
N. VICTOR JAYA ◽  
S. NATARAJAN
Keyword(s):  
High Pressure ◽  
Zinc Concentration ◽  
Structural Phase ◽  
Structural Studies ◽  
Superconducting Transition ◽  
High Pressure Synthesis ◽  
Tetragonal System ◽  
Phase Compound ◽  
Pressure Synthesis ◽  
Pressure Phase

High pressure synthesis and structural studies on the reported high pressure phase compound ( Ca 0.3 Sr 0.7)0.9 CuO 2 have been carried out using zinc. Substitution of zinc seriously affects the superconducting transition temperature T c , which gets lowered to around 60 K for the x=0.1 compound. Further increase in zinc concentration destroys superconductivity. All the compounds could be well indexed to the tetragonal system with little variation in lattice parameters showing structural phase stability.

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