View EntryDate of entry : 08/11/2010


Combined X-ray single crystal and neutron powder refinement of modulated
structures and application to the incommensurately modulated structure of
Bi2Sr2CaCu2O8+y

Gao, Y.; Coppens, P.; Cox, D.E.; Moodenbaugh, A.R. Acta Cryst. A 49 141 - 148 (1993)

[ B-IncStrDB ID: 312EZB5Wy ]
 
Submitted by : System [B-IncStrDB]CIF File

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Bi2Sr2CaCu2O8+y_MOD

Chemical Properties

Structural Formula Sum: Bi1.98 Ca0.96 Cu2 O8.14 Sr1.75   [Help]
Weight: 862.9 Daltons  [Help]

Crystallographic Properties

Exp. Crystal Type of Struc.: mod   [Help]
a: 5.415(3) Å  [Help]
b: 5.4149(5) Å  [Help]
c: 30.861(5) Å  [Help]
α: 90 °  [Help]
β: 90 °  [Help]
γ: 90 °  [Help]
Volume: 904.9(18) Å3  [Help]
Crystal System: orthorhombic   [Help]
Space Group Name (H-M): A 2 a a   [Help]
Space Group Name: X2aa(α00)000   [Help]
Number of Formula Units: 4   [Help]

  •  Additional Crystal Information   

Experimental Data

Experimental Special Details:
Measured composition Bi2.12(10) Sr1.79(10) Ca0.92(5) Cu2
Superspace group taken from:
Petricek, Gao, Lee & Coppens
Phys. Rev. (1990) B42, 387-392
  [Help]

Radiation source: X-rays and neutrons (λ=2.373 \%A)   [Help]
Max Order of Satellite Reflections: 2   [Help]

  •  Additional Experimental Information   

Refinement Properties

Modulation function desc.:
Displacive modulation for Bi, Sr, Cu, Ca, O(1), O(2) and O(3) sites:Fourier
series. Up to 2nd-order harmonics. Modulation of O(4) atoms described by
a sawtooth function. Modulation of temperature factors for Bi sites:Fourier
series. Up to 2nd-order harmonics.
  [Help]

Structure factors calc. details: Bessel functions   [Help]
# of observed reflections: 2001   [Help]
factors for all reflns.: 0.092   [Help]
Experimental Special Details:
Measured composition Bi2.12(10) Sr1.79(10) Ca0.92(5) Cu2
Superspace group taken from:
Petricek, Gao, Lee & Coppens
Phys. Rev. (1990) B42, 387-392
  [Help]

Refinement Special Details:
A combined refinement using single crystal X-ray and powder neutrons.

WARNING: The published displacement parameters have been converted to relative
units. The calculated standard uncertainties (s.u.) have been based uniquely on
the published ones without considering the s.u. of any other quantity involved
in such conversion.
  [Help]

  •  Additional Refinement Information   

Diffraction Data

Radiation source: X-rays and neutrons (λ=2.373 \%A)   [Help]


  •  Reference Structure Information   

  •  Modulation Parameters (Tables)   

  •  Refinement Summary   

  •  Modulation Parameters (Atom Sites Summary)