Manganese disilicide (MnSi₂) is an intermetallic compound, a silicide of manganese. It is a non-stoichiometric compound, with a silicon deficiency 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.^[5]

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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.
Magnetic susceptibility (χ)	0.7×10−6 emu/g (MnSi1.72)[3]
Structure
Crystal structure	Tetragonal[4]
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
Related compounds	Manganese monosilicide
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

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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.^[5]