Molybdenum disilicide

Names
IUPAC name

Molybdenum disilicide

Other names

Molybdenum(VIII) silicide

Identifiers

CAS Number

* 12136-78-6 Y

3D model (JSmol)

* Interactive image

ChemSpider |

* 8329647

ECHA InfoCard | 100.032.016
EC Number |

* 235-231-8

PubChem CID

* 6336985

CompTox Dashboard (EPA)

* DTXSID601014284

InChI

* InChI=1S/Mo.2Si

Key: YXTPWUNVHCYOSP-UHFFFAOYSA-N

SMILES

* [Si]=[Mo]=[Si]

Properties

Chemical formula

| MoSi2
Molar mass | 152.11 g/mol
Appearance  | gray metallic solid
Density | 6.26 g/cm3[1][2]
Melting point | 2,030 °C (3,690 °F; 2,300 K)[2]
Structure

Crystal structure

| Tetragonal[1]

Space group

| I4/mmm (No. 139), tI6

Lattice constant

a = 0.32112 nm, c = 0.7845 nm

Formula units (Z)

| 2
Hazards
GHS labelling:[1]

Pictograms

Signal word

| Warning

Hazard statements

| H301, H312, H332

Precautionary statements

| P261, P264, P270, P271, P280, P301+P317, P302+P352, P304+P340, P317, P321, P330, P362+P364, P501
Flash point | Non-flammable
Related compounds

Other cations

| Chromium disilicide
Tungsten disilicide

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

N verify (what is YN ?)

Infobox references

Chemical compound

Molybdenum disilicide (MoSi2, or molybdenum silicide), an intermetallic compound, a silicide of molybdenum, is a refractory ceramic with primary use in heating elements. It has moderate density, melting point 2030 °C, and is electrically conductive. At high temperatures it forms a passivation layer of silicon dioxide, protecting it from further oxidation. The thermal stability of MoSi2 alongside its high emissivity make this material, alongside WSi2 attractive for applications as a high emissivity coatings in heat shields for atmospheric entry.[3] MoSi2 is a gray metallic-looking material with tetragonal crystal structure (alpha-modification); its beta-modification is hexagonal and unstable.[4] It is insoluble in most acids but soluble in nitric acid and hydrofluoric acid.

While MoSi2 has excellent resistance to oxidation and high Young's modulus at temperatures above 1000 °C, it is brittle in lower temperatures. Also, at above 1200 °C it loses creep resistance. These properties limits its use as a structural material, but may be offset by using it together with another material as a composite material.

Molybdenum disilicide and MoSi2-based materials are usually made by sintering. Plasma spraying can be used for producing its dense monolithic and composite forms; material produced this way may contain a proportion of β-MoSi2 due to its rapid cooling.

Molybdenum disilicide heating elements can be used for temperatures up to 1800 °C, in electric furnaces used in laboratory and production environment in production of glass, steel, electronics, ceramics, and in heat treatment of materials. While the elements are brittle, they can operate at high power without aging, and their electrical resistivity does not increase with operation time. Their maximum operating temperature has to be lowered in atmospheres with low oxygen content due to breakdown of the passivation layer.[5]

Molybdenum disilicide is used in microelectronics as a contact material. It is often used as a shunt over polysilicon lines to increase their conductivity and increase signal speed.

## See also

[edit]

* Silicon carbide

## References

[edit]

1. ^ a b A. Nørlund Christensen (1993). "Crystal growth and characterization of the transition metal silicides MoSi2 and WSi2". Journal of Crystal Growth. 129 (1–2): 266–268\. Bibcode:1993JCrGr.129..266N. doi:10.1016/0022-0248(93)90456-7.1–2&rft.pages=266-268&rft.date=1993&rft_id=info:doi/10.1016/0022-0248(93)90456-7&rft_id=info:bibcode/1993JCrGr.129..266N&rft.au=A.+Nørlund+Christensen&rfr_id=info:sid/en.wikipedia.org:Molybdenum+disilicide" class="Z3988">
2. ^ a b Soo-Jin Park; Min-Kang Seo (2011). Interface Science and Composites. Academic Press. pp. 563–. ISBN 978-0-12-375049-5.
3. ^ High emissivity coatings on fibrous ceramics for reusable space systems Corrosion Science 2019
4. ^ F. M. d’Heurle, C. S. Petersson, and M. Y. Tsai (1980). "Observations on the hexagonal form of MoSi2 and WSi2 films produced by ion implantation and on related snowplow effects". J. Appl. Phys. 51 (11): 5976–5980\. Bibcode:1980JAP....51.5976D. doi:10.1063/1.327517.5976-5980&rft.date=1980&rft_id=info:doi/10.1063/1.327517&rft_id=info:bibcode/1980JAP....51.5976D&rft.au=F.+M.+d’Heurle,+C.+S.+Petersson,+and+M.+Y.+Tsai&rfr_id=info:sid/en.wikipedia.org:Molybdenum+disilicide" class="Z3988">`{{cite journal}}`: CS1 maint: multiple names: authors list (link)
5. ^ Park, S.J.; Seo, M.K. (2011). Interface Science and Composites. Interface Science and Technology. Elsevier Science. p. 563\. ISBN 978-0-12-375049-5. Retrieved 2023-09-09.

* v
* t
* e

Molybdenum compounds

Mo(0)|

* Mo(CO)6
* Mo3P

Mo(II)|

* MoBr2
* MoCl2
* MoI2
* MoSi2

Mo(III)|

* MoBr3
* MoCl3
* MoI3
* Mo2O3
* Mo2(OtBu)6
* MoP

Mo(IV)|

* MoBr4
* MoCl4
* MoF4
* MoO2
* MoS2
* MoSe2
* MoTe2
* MoP2
* MoAs2

Mo(V)|

* MoCl5
* MoF5
* Mo2O5

Mo(VI)|

* Molybdates
* Molybdic acid
* MoO3
* MoCl6
* MoOF4
* MoOCl4
* MoF2O2
* MoO2Cl2
* MoF6
* MoS3

* v
* t
* e

Salts and covalent derivatives of the silicide ion

| SiH4
+H |  |  |  | He

|
|
|
|

LiSi | Be2Si | SiB3
SiB6
+B | SiC
+C | Si3N4

+N | SiO2 | SiF4 | Ne
NaSi | Mg2Si | Al  | Si4− | SiP, SiP2

+P | SiS2
-S | SiCl4 | Ar
KSi | CaSi
CaSi2 |  | ScSi Sc5Si3 Sc2Si3 Sc5Si4 | TiSi
TiSi2 | V3Si V5Si3, V6Si5, VSi2, V6Si5 | Cr3Si Cr5Si3, CrSi, CrSi2 | MnSi, MnSi2, Mn9Si2, Mn3Si, Mn5Si3, Mn11Si9 | FeSi2
FeSi
Fe5Si3
Fe2Si
Fe3Si | CoSi, CoSi2, Co2Si, Co3Si  | NiSi, more… | Cu17Si3, Cu56Si11, Cu5Si, Cu33Si7, Cu4Si, Cu19Si6, Cu3Si, Cu87Si13 | Zn  | Ga  | GeSi
+Ge | SiAs, SiAs2
-As
+As | SiSe2 SiSe  | SiBr4 | Kr
RbSi | SrSi2 |  | YSi Y5Si3, Y5Si4, Y3Si5, YSi1.4 | ZrSi Zr5Si3, Zr5Si4, ZrSi2, Zr3Si2, Zr2Si, Zr3Si  | Nb4Si Nb5Si3 | MoSi2
Mo3Si Mo5Si3 | Tc  | RuSi Ru2Si, Ru4Si3, Ru2Si3 | RhSi Rh2Si, Rh5Si3, Rh3Si2, Rh20Si13 | PdSi Pd5Si, Pd9Si2, Pd3Si, Pd2Si  | Ag  | Cd  | In  | Sn  | Sb  | TeSi2 Te2Si3 | SiI4 | Xe
CsSi | Ba2Si BaSi2, Ba5Si3 Ba3Si4 | *  | Lu5Si3 | HfSi Hf2Si, Hf3Si2, Hf5Si4, HfSi2 | Ta9Si2, Ta3Si, Ta5Si3 | WSi2 W5Si3 | ReSi Re2Si, ReSi1.8 Re5Si3 | OsSi | IrSi | PtSi | Au  | Hg  | Tl  | Pb  | Bi  | Po  | At  | Rn
Fr  | Ra  | **  | Lr  | Rf  | Db  | Sg  | Bh  | Hs  | Mt  | Ds  | Rg  | Cn  | Nh  | Fl  | Mc  | Lv  | Ts  | Og

*  | LaSi2 La5Si3, La3Si2, La5Si4, LaSi  | CeSi2 Ce5Si3, Ce3Si2, Ce5Si4, CeSi, Ce3Si5 | PrSi2 Pr5Si3, Pr3Si2, Pr5Si4, PrSi  | NdSi Nd5Si3, Nd5Si4, Nd5Si3, Nd3Si4, Nd2Si3, NdSix | Pm  | SmSi2 Sm5Si4, Sm5Si3, SmSi, Sm3Si5 | Eu?  | GdSi2 Gd5Si3, Gd5Si4, GdSi  | TbSi2 SiTb, Si4Tb5, Si3Tb5 | DySi2 DySi  | HoSi2 Ho5Si3, Ho5Si4, HoSi, Ho4Si5 | ErSi2 Er5Si3, Er5Si4, ErSi  | Tm?  | YbSi Si1.8Yb, Si5Yb3, Si4Yb3, Si4Yb5, Si3Yb5
**  | Ac  | ThSi | PaSi | USi2 | NpSi2 | PuSi | Am  | Cm  | Bk  | Cf  | Es  | Fm  | Md  | No
*[CID]: Compound ID
*[EPA]: U.S. Environmental Protection Agency
*[H301]: H301: Toxic if swallowed
*[H312]: H312: Harmful in contact with skin
*[H332]: H332: Harmful if inhaled
*[P261]: P261: Avoid breathing dust/fume/gas/mist/vapours/spray.
*[P264]: P264: Wash ... thoroughly after handling.
*[P270]: P270: Do not eat, drink or smoke when using this product.
*[P271]: P271: Use only outdoors or in a well-ventilated area.
*[P280]: P280: Wear protective gloves/protective clothing/eye protection/face protection.
*[P301+P317]: P301+P317: IF SWALLOWED: IF SWALLOWED: Get medical help.
*[P302+P352]: P302+P352: IF ON SKIN: Wash with soap and water.
*[P304+P340]: P304+P340: IF INHALED: Remove victim to fresh air and keep at rest in a position comfortable for breathing.
*[P317]: P317: Get emergency medical help.
*[P321]: P321: Specific treatment (see ... on this label).
*[P330]: P330: Rinse mouth.
*[P362+P364]: P362+P364: Take off contaminated clothing and wash it before reuse.
*[P501]: P501: Dispose of contents/container to ...
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