Bismuth antimonide

Bismuth antimonide  Identifiers

CAS Number

* 12323-19-2

3D model (JSmol)

* Interactive image

ChemSpider |

* 11201349

PubChem CID

* 69145232.1.1InChI

InChI

* InChI=1S/2Bi.2Sb

* Key: AEMQIQQWIVNHAU-UHFFFAOYSA-N

SMILES

* [Sb].[Sb].[Bi].[Bi]

Properties

Chemical formula

| BiSb
Molar mass | 330.74 g/mol
Appearance  | Faint-grey to dark-grey powder
Density | 8.31 g/cm3
Solubility | insoluble
Structure

Crystal structure

| Hexagonal, A7, SpaceGroup = R-3m, No. 166

Lattice constant

a = 4.546A, c = 11.860A[1]

Hazards
Safety data sheet | [1]
GHS pictograms |
GHS Signal word | Warning

GHS hazard statements

| H302, H332, H411
NFPA 704 (fire diamond)  |

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Infobox references

Bismuth antimonides, Bismuth-antimonys, or Bismuth-antimony alloys, (Bi1−xSbx) are binary alloys of bismuth and antimony in various ratios.

Some, in particular Bi0.9Sb0.1, were the first experimentally-observed three-dimensional topological insulators, materials that have conducting surface states but have an insulating interior.[2]

Various BiSb alloys also superconduct at low temperatures,[3] are semiconductors,[1] and are used in thermoelectric devices.[4]

Bismuth antimonide itself (see box to right) is sometimes described as Bi2Sb2.[5]

## Contents

* 1 Synthesis
* 2 Properties
* 2.1 Topological insulator
* 2.2 Superconductor
* 2.3 Semiconductor
* 2.4 Thermoelectric
* 3 References

## Synthesis

Crystals of bismuth antimonides are synthesized by melting bismuth and antimony together under inert gas or vacuum. Zone melting is used to decrease the concentration of impurities.[4] When synthesizing single crystals of bismuth antimonides, it is important that impurities are removed from the samples, as oxidation occurring at the impurities leads to polycrystalline growth.[1]

## Properties

### Topological insulator

Pure bismuth is a semimetal, containing a small band gap, which leads to it having a relatively high conductivity (7.7×105 S/m at 20 °C). When the bismuth is doped with antimony, the conduction band decreases in energy and the valence band increases in energy. At an antimony concentration of 4%, the two bands intersect, forming a Dirac point[2] (which is defined as a point where the conduction and valence bands intersect). Further increases in the concentration of antimony result in a band inversion, in which the energy of the valence band becomes greater than that of the conduction band at specific momenta. Between Sb concentrations of 7 and 22%, the bands no longer intersect, and the Bi1−xSbx becomes an inverted-band insulator.[6] It is at these higher concentrations of Sb that the band gap in the surface states vanishes, and the material thus conducts at its surface.[2]

### Superconductor

The highest temperatures at which Bi0.4Sb0.6, as a thin film of thicknesses 150–1350 Å, superconducts (the critical temperature Tc) is approximately 2 K.[3] Single crystal Bi0.935Sb0.065 can superconduct at slightly higher temperatures, and at 4.2 K, its critical magnetic field Bc (the maximum magnetic field that the superconductor can expel) of 1.6 T at 4.2 K.[7]

### Semiconductor

Electron mobility is one important parameter describing semiconductors because it describes the rate at which electrons can travel through the semiconductor. At 40 K, electron mobility ranged from 4.9×105 cm2/V·s at an antimony concentration of 0 to 2.4×105 cm2/V·s at an antimony concentration of 7.2%.[1] This is much greater than the electron mobility of other common semiconductors like silicon, which is 1400 cm2/V·s at room temperature.[8]

Another important parameter of Bi1−xSbx is the effective electron mass (EEM), a measure of the ratio of the acceleration of an electron to the force applied to an electron. The effective electron mass is 2×10−3 me for x = 0.11 and 9×10−4 me at x = 0.06.[2] This is much less than the electron effective mass in many common semiconductors (1.09 in Si at 300 K, 0.55 in Ge, and 0.067 in GaAs). A low EEM is good for Thermophotovoltaic applications.

### Thermoelectric

Bismuth antimonides are used as the n-type legs in many thermoelectric devices below room temperature. The thermoelectric efficiency, given by its figure of merit zT = ⁠σS2T/λ⁠, where S is the Seebeck coefficient, λ is the thermal conductivity, and σ is the electrical conductivity, describes the ratio of the energy provided by the thermoelectric to the heat absorbed by the device. At 80 K, the figure of merit (zT) for Bi1−xSbx peaks at 6.5×10−3 K−1 when x = 0.15.[4] Also, the Seebeck coefficient (the ratio of the potential difference between ends of a material to the temperature difference between the sides) at 80 K of Bi0.9Sb0.1 is −140 μV/K, much lower than the Seebeck coefficient of pure bismuth, −50 μV/K.[9]

## References

1. ↑ 1.0 1.1 1.2 1.3 Jain, A. L. (1959). "Temperature Dependence of the Electrical Properties of Bismuth-Antimony Alloys". Physical Review 114 (6): 1518–1528. doi:10.1103/physrev.114.1518. Bibcode: 1959PhRv..114.1518J.
2. ↑ 2.0 2.1 2.2 2.3 Hsieh, D.; Qian, D.; Wray, L.; Xia, Y.; Hor, Y. S.; Cava, R. J.; Hasan, M. Z. (2008-04-24). "A topological Dirac insulator in a quantum spin Hall phase". Nature 452 (7190): 970–974. doi:10.1038/nature06843. ISSN 0028-0836. PMID 18432240. Bibcode: 2008Natur.452..970H. http://www.nature.com/nature/journal/v452/n7190/full/nature06843.html.
3. ↑ 3.0 3.1 Zally, G. D.; Mochel, J. M. (1971). "Fluctuation Heat Capacity in Superconducting Thin Films of Amorphous BiSb". Physical Review Letters 27 (25): 1710–1712. doi:10.1103/physrevlett.27.1710. Bibcode: 1971PhRvL..27.1710Z.
4. ↑ 4.0 4.1 4.2 Smith, G. E.; Wolfe, R. (1962-03-01). "Thermoelectric Properties of Bismuth-Antimony Alloys". Journal of Applied Physics 33 (3): 841–846. doi:10.1063/1.1777178. ISSN 0021-8979. Bibcode: 1962JAP....33..841S.
5. ↑ PubChem. "Bismuth, compd. with antimony (1:1)" (in en). https://pubchem.ncbi.nlm.nih.gov/compound/6914523.
6. ↑ Shuichi Murakami (2007). "Phase transition between the quantum spin Hall and insulator phases in 3D: emergence of a topological gapless phase". New Journal of Physics 9 (9): 356. doi:10.1088/1367-2630/9/9/356. Bibcode: 2007NJPh....9..356M.
7. ↑ Kasumov, A. Yu.; Kononenko, O. V.; Matveev, V. N.; Borsenko, T. B.; Tulin, V. A.; Vdovin, E. E.; Khodos, I. I. (1996). "Anomalous Proximity Effect in the Nb–BiSb–Nb Junctions". Physical Review Letters 77 (14): 3029–3032. doi:10.1103/physrevlett.77.3029. PMID 10062113. Bibcode: 1996PhRvL..77.3029K.
8. ↑ "Electrical properties of Silicon (Si)". http://www.ioffe.rssi.ru/SVA/NSM/Semicond/Si/electric.html.
9. ↑ Goldsmid, H. J. (1970-01-16). "Bismuth–antimony alloys". Physica Status Solidi A 1 (1): 7–28. doi:10.1002/pssa.19700010102. ISSN 1521-396X. Bibcode: 1970PSSAR...1....7G.

Template:Antimonides

* v
* t
* e

Bismuth compounds

Bismuth(III)|

* BiBr3
* BiCl3
* Bi4Ge3O12
* BiOCl
* Bi2Se3
* Bi12SiO20
* Bi2O2(CO3)
* Bi2Te3
* BiF3
* BiI3
* Bi(NO3)3
* Bi2O3
* Bi(OH)3
* Bi2S3
* BiH3
* BiOHOCOC6H4O

| Organobismuth(III)|

* C4H4BiH

|

Bismuth(V)|

* NaBiO3
* BiF5
* Bi2O5

* v
* t
* e

Antimony compounds

* SbBr3
* Sb(C2H3O2)3
* SbCl3
* SbCl5
* SbF3
* SbF5
* SbH3
* SbI3
* Sb2O3
* Sb2O4
* Sb2O5
* Sb2S3
* Sb2S5
* Sb2(SO4)3
* Sb2Se3
* Sb2Te3

0.00

(0 votes)

Original source: https://en.wikipedia.org/wiki/Bismuth antimonide. Read more

|

Retrieved from "https://handwiki.org/wiki/index.php?title=Chemistry:Bismuth_antimonide&oldid=4267454"
*[CID]: Compound ID
*[H302]: Harmful if swallowed
*[H332]: Harmful if inhaled
*[H411]: Toxic to aquatic life with long lasting effects
*[v]: View this template
*[t]: Discuss this template
*[e]: Edit this template