Manganese disilicide

Manganese disilicide (MnSi₂) is an intermetallic compound, a silicide of manganese. It is a non-stoichiometric compound, with a silicon defficiency expressed as MnSi_2–x. Crystal structures of many MnSi_2–x compounds resemble a chimney ladder and are called Nowotny phases. They include MnSi₂ (x=0), Mn₄Si₇ (x=0.250), Mn₁₁Si₁₉ (x=0.273), Mn₁₅Si₂₆ (x=0.267) and Mn₂₇Si₄₇ (x=0.259). These phases have very similar unit cells whose length varies from 1.75 nm for MnSi₂ or Mn₄Si₇, which have almost the same structures, to 11.8 nm for Mn₂₇Si₄₇.[4]

Mn₄Si₇ structure

Manganese disilicide

Electron micrograph of MnSi2 stars grown on Si plates
Names
IUPAC name Manganese disilicide
Identifiers
CAS Number	12032-86-9^Y
3D model (JSmol)	Interactive image
ChemSpider	4891874
ECHA InfoCard	100.031.606
EC Number	234-781-6
PubChem CID	6336881
InChI InChI=1S/Mn.2Si Key: FHTCLMVMBMJAEE-UHFFFAOYSA-N
SMILES [Si]=[Mn]=[Si]
Properties
Chemical formula	MnSi2
Molar mass	111.109 g/mol
Appearance	gray crystals[1]
Melting point	1,152 °C (2,106 °F; 1,425 K)[1][2] dec.
Structure
Crystal structure	Tetragonal[3]
Space group	P4c2 (No. 116), tP44
Lattice constant	a = 0.5518 nm, c = 1.7449 nm
Formula units (Z)	4
Hazards
Flash point	Non-flammable
Related compounds
Other cations	Cobalt disilicide Iron disilicide Titanium disilicide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N (what is ^YN ?)
Infobox references

MnSi_2–x Nowotny phases have a Mn sublattice with a β-tin structure overlaid with a face-centered cubic Si sublattice. They resemble chimneys of transition metal atoms containing spiraling ladders of Si. These phases are semiconductors with a band gap of 0.4 to 0.9 eV. They exhibit a reasonably high thermoelectric figure of merit ZT ~ 0.8 and have potential applications in thermoelectric generators.[4]

References

1. Haynes, William M., ed. (2016). CRC Handbook of Chemistry and Physics (97th ed.). CRC Press. p. 4.73. ISBN 9781498754293.
2. Levinson, Lionel M. (1973). "Investigation of the defect manganese silicide Mn_nSi_2n−m". Journal of Solid State Chemistry. 6 (1): 126–135. doi:10.1016/0022-4596(73)90212-0.
3. Shin, Yooleemi; Rhim, Sung Hyon; Duong, Anh Tuan; Nguyen, Van Quang; Hong, Soon Cheol; Cho, Sunglae; Park, Hyun-Min (2015). "New synthesis of MnSi₂ thin film and its thermoelectric properties". Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films. 33 (6): 061516. doi:10.1116/1.4932515. ISSN 0734-2101.
4. Higgins, Jeremy M.; Schmitt, Andrew L.; Guzei, Ilia A.; Jin, Song (2008). "Higher Manganese Silicide Nanowires of Nowotny Chimney Ladder Phase". Journal of the American Chemical Society. 130 (47): 16086–16094. doi:10.1021/ja8065122.