Extremely long period-stacking structure in the Sb–Te binary system

Kifune, K.; Kubota, Y.; Matsunaga, T.; Yamada, N.

doi:10.1107/S0108768105017714

Extremely long period-stacking structure in the Sb–Te binary system

K. Kifune, Y. Kubota, T. Matsunaga and N. Yamada

The crystal structure of the δ-phase in the Sb–Te binary system has been determined by synchrotron powder diffraction. It is clearly shown that many intermetallic compounds, which have different stacking periods depending on compound composition, exist in this phase. These structures are based on the cubic ABC stacking structure, and two kinds of fundamental structural units form an intergrowth along the stacking direction at the atomic level. The chemical formulae of these compounds are expressed as Sb_2nTe₃, where n is an integer and the number of stacking layers is 2n + 3. There is a relationship of inverse proportionality between the stacking period and the Te concentration.

Keywords: optical recording media; high-speed phase changes; Sb–Te binary compounds; X-ray diffraction.

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Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S0108768105017714/og5010sup1.cif Contains datablocks SbTe, Sb72Te28, Sb85Te15
	Rietveld powder data file (CIF format) https://doi.org/10.1107/S0108768105017714/og5010sb72te28sup2.rtv Contains datablock sb72te28
	Rietveld powder data file (CIF format) https://doi.org/10.1107/S0108768105017714/og5010sb85te15sup3.rtv Contains datablock sb85te15

Computing details top

Figures top

(Sb72Te28) top

Crystal data top

Sb₇₂Te₂₈	V = 1009.51 (1) Å³
M_r = ?	Z = ?
Trigonal, R3m:h	Synchrotron radiation, λ = 0.42137 Å
Hall symbol: -R 3 2"	T = 90 K
a = 4.27125 (2) Å	?, ? × ? × ? mm
c = 63.8957 (6) Å

Data collection top

Debye-Scherrer diffractometer	Scan method: step
Radiation source: synchrotron	2θ_min = 2.000°, 2θ_max = 72.000°, 2θ_step = 0.010°
Si monochromator

Refinement top

Refinement on I_net	7001 data points
R_p = 0.047	Profile function: split-PearsonVII
R_wp = 0.066	w = 1/[Y_i]
R_exp = 0.021
R_Bragg = 0.042	Background function: at first background curve was provided by ; the combination of split-PearsonVII function, and the parameters of the ; function were refined to fit to the experimental data.
χ² = 9.364	Preferred orientation correction: none

Crystal data top

Sb₇₂Te₂₈	V = 1009.51 (1) Å³
M_r = ?	Z = ?
Trigonal, R3m:h	Synchrotron radiation, λ = 0.42137 Å
a = 4.27125 (2) Å	T = 90 K
c = 63.8957 (6) Å	?, ? × ? × ? mm

Data collection top

Debye-Scherrer diffractometer	2θ_min = 2.000°, 2θ_max = 72.000°, 2θ_step = 0.010°
Scan method: step

Refinement top

R_p = 0.047	R_Bragg = 0.042
R_wp = 0.066	χ² = 9.364
R_exp = 0.021	7001 data points

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	B_iso*/B_eq
Te1	0.000000	0.000000	0.000000	0.32 (1)*
Sb1	0.333333	0.666667	0.03290 (4)	0.67 (1)*
Te2	0.666667	0.333333	0.05840 (3)	0.32 (1)*
Sb2	0.000000	0.000000	0.09430 (4)	0.67 (1)*
Sb3	0.333333	0.666667	0.11846 (4)	0.67 (1)*
Sb4	0.666667	0.333333	0.15457 (4)	0.67 (1)*

(Sb85Te15) top

Crystal data top

Sb₈₅Te₁₅	V = 1725.82 (2) Å³
M_r = ?	Z = ?
Trigonal, R3m:h	Synchrotron radiation, λ = 0.42137 Å
Hall symbol: -R 3 2"	T = 90 K
a = 4.28168 (2) Å	?, ? × ? × ? mm
c = 108.7017 (8) Å

Data collection top

Debye-Scherrer diffractometer	Scan method: step
Radiation source: synchrotron	2θ_min = 2.000°, 2θ_max = 72.000°, 2θ_step = 0.010°
Si monochromator

Refinement top

Refinement on I_net	7001 data points
R_p = 0.047	Profile function: split-PearsonVII
R_wp = 0.065	w = 1/[Y_i]
R_exp = 0.024
R_Bragg = 0.033	Background function: at first background curve was provided by ; the combination of split-PearsonVII function, and the parameters of the ; function were refined to fit to the experimental data.
χ² = 7.562	Preferred orientation correction: none

Crystal data top

Sb₈₅Te₁₅	V = 1725.82 (2) Å³
M_r = ?	Z = ?
Trigonal, R3m:h	Synchrotron radiation, λ = 0.42137 Å
a = 4.28168 (2) Å	T = 90 K
c = 108.7017 (8) Å	?, ? × ? × ? mm

Data collection top

Debye-Scherrer diffractometer	2θ_min = 2.000°, 2θ_max = 72.000°, 2θ_step = 0.010°
Scan method: step

Refinement top

R_p = 0.047	R_Bragg = 0.033
R_wp = 0.065	χ² = 7.562
R_exp = 0.024	7001 data points

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	B_iso*/B_eq
Te1	0.000000	0.000000	0.000000	0.20 (2)*
Sb1	0.666667	0.333333	0.01902 (3)	0.406 (7)*
Te2	0.333333	0.666667	0.03413 (3)	0.20 (2)*
Sb2	0.000000	0.000000	0.05560 (3)	0.406 (7)*
Sb3	0.666667	0.333333	0.06931 (3)	0.406 (7)*
Sb4	0.333333	0.666667	0.08982 (3)	0.406 (7)*
Sb5	0.000000	0.000000	0.10426 (3)	0.406 (7)*
Sb6	0.666667	0.333333	0.12508 (3)	0.406 (7)*
Sb7	0.333333	0.666667	0.13886 (3)	0.406 (7)*
Sb8	0.000000	0.000000	0.15972 (3)	0.406 (7)*

Experimental details

	(Sb72Te28)	(Sb85Te15)
Crystal data
Chemical formula	Sb₇₂Te₂₈	Sb₈₅Te₁₅
M_r	?	?
Crystal system, space group	Trigonal, R3m:h	Trigonal, R3m:h
Temperature (K)	90	90
a, c (Å)	4.27125 (2), 63.8957 (6)	4.28168 (2), 108.7017 (8)
V (Å³)	1009.51 (1)	1725.82 (2)
Z	?	?
Radiation type	Synchrotron, λ = 0.42137 Å	Synchrotron, λ = 0.42137 Å
Specimen shape, size (mm)	?, ? × ? × ?	?, ? × ? × ?

Data collection
Diffractometer	Debye-Scherrer diffractometer	Debye-Scherrer diffractometer
Specimen mounting	?	?
Data collection mode	?	?
Scan method	Step	Step
2θ values (°)	2θ_min = 2.000 2θ_max = 72.000 2θ_step = 0.010	2θ_min = 2.000 2θ_max = 72.000 2θ_step = 0.010

Refinement
R factors and goodness of fit	R_p = 0.047, R_wp = 0.066, R_exp = 0.021, R_Bragg = 0.042, χ² = 9.364	R_p = 0.047, R_wp = 0.065, R_exp = 0.024, R_Bragg = 0.033, χ² = 7.562
No. of data points	7001	7001
No. of parameters	?	?
No. of restraints	?	?

Format		BIBTeX
		EndNote
		RefMan
		Refer
		Medline
		CIF
		SGML
		Text
		Plain Text

Format		BIBTeX
		EndNote
		RefMan
		Refer
		Medline
		CIF
		SGML
		Text
		Plain Text

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