Manganese disilicide (MnSi2) is an intermetallic compound, a silicide of manganese. It is a non-stoichiometric compound, with a silicon deficiency expressed as MnSi2–x. Crystal structures of many MnSi2–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.[5]
 Electron micrograph of MnSi2 stars grown on Si plates
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| Names | |
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| IUPAC name
Manganese disilicide
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| Identifiers | |
3D model (JSmol)
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| ChemSpider | |
| ECHA InfoCard | 100.031.606 |
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PubChem CID
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| Properties | |
| MnSi2 | |
| Molar mass | 111.109 g/mol |
| Appearance | gray crystals[1] |
| Melting point | 1,152 °C (2,106 °F; 1,425 K)[1][3] dec. |
| 0.7×10−6 emu/g (MnSi1.72)[2] | |
| Structure | |
| Tetragonal[4] | |
| P4c2 (No. 116), tP44 | |
a = 0.5518 nm, c = 1.7449 nm
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Formula units (Z)
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4 |
| Hazards | |
| Flash point | Non-flammable |
| Related compounds | |
Other cations
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Cobalt disilicide Iron disilicide Titanium disilicide |
Related compounds
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Manganese monosilicide |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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MnSi2–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.[5]
References
edit- ^ a b Haynes, William M., ed. (2016). CRC Handbook of Chemistry and Physics (97th ed.). CRC Press. p. 4.73. ISBN 9781498754293.
- ^ Shinoda, Daizaburo; Asanabe, Sizuo (1966). "Magnetic Properties of Silicides of Iron Group Transition Elements". Journal of the Physical Society of Japan. 21 (3): 555. Bibcode:1966JPSJ...21..555S. doi:10.1143/JPSJ.21.555.
- ^ Levinson, Lionel M. (1973). "Investigation of the defect manganese silicide MnnSi2n−m". Journal of Solid State Chemistry. 6 (1): 126–135. Bibcode:1973JSSCh...6..126L. doi:10.1016/0022-4596(73)90212-0.
- ^ 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. Bibcode:2015JVSTA..33f1516S. doi:10.1116/1.4932515. ISSN 0734-2101.
- ^ a b 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. PMID 18983151.