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Pentamagnesium digallide
Names
	IUPAC name Pentamagnesium digallide
	Other names Magnesium gallide(−V);
Identifiers
CAS Number	12064-14-1 ;
3D model (JSmol)	Interactive image;
PubChem CID	78062207;
CompTox Dashboard (EPA)	DTXSID30779590;
	InChI InChI=1S/2Ga.5Mg Key: BHKRUXZCMMTJBB-UHFFFAOYSA-N;
	SMILES [Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Ga-5].[Ga-5];
Properties
Chemical formula	Mg5Ga2
Molar mass	260.97 g/mol
Appearance	White crystalline solid
Density	3.08 g/cm3
Melting point	456 °C (853 °F; 729 K)
Structure
Crystal structure	Orthorhombic
Space group	Ibam
Point group	mmm
Lattice constant	a = 13.71 Å, b = 7.02 Å, c = 6.02 Å
Lattice volume (V)	579.06 Å3
Thermochemistry
Std enthalpy of; formation (ΔfH⦵298)	-206.5 kJ/mol (calculated)
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Pentamagnesium digallide, also known as magnesium gallide(−V), is a chemical compound in the family of magnesium gallides (Mg_xGa_y). This compound has gallium in the rare oxidation state −5 and is produced by splat quenching of a molten mixture of magnesium and gallium metal then heating the resulting substance to 350 °C:^[1]^[2]

5Mg + 2Ga → Mg₅Ga₂

It is an unwanted product when magnesium-gallium alloys are exposed to high temperatures.^[3]

References

^ Bruno Predel; Knut Hülse (1979). "Metastabile kristalline und glasartige phasen im system Magnesium-Gallium". Journal of the Less Common Metals. 63 (1): 45–56. doi:10.1016/0022-5088(79)90207-8.
^ Patrick Hofmann. "Colture. Ein Programm zur interaktiven Visualisierung von Festkörperstrukturen sowie Synthese, Struktur und Eigenschaften von binären und ternären Alkali- und Erdalkalimetallgalliden" (PDF) (in German). p. 72.
^ Yan Feng; Ri-chu Wang; Chao-qun Peng; Hui-ping Tang; Hai-yan Liu (2011). "Influence of Mg5Ga2 compound on microstructures and electrochemical properties of Mg-5%Hg-22%Ga alloy". Progress in Natural Science: Materials International. 21 (1): 73–79. doi:10.1016/S1002-0071(12)60028-8.

[cry-1] Bruno Predel; Knut Hülse (1979). "Metastabile kristalline und glasartige phasen im system Magnesium-Gallium". Journal of the Less Common Metals. 63 (1): 45–56. doi:10.1016/0022-5088(79)90207-8.

[2] Patrick Hofmann. "Colture. Ein Programm zur interaktiven Visualisierung von Festkörperstrukturen sowie Synthese, Struktur und Eigenschaften von binären und ternären Alkali- und Erdalkalimetallgalliden" (PDF) (in German). p. 72.

[3] Yan Feng; Ri-chu Wang; Chao-qun Peng; Hui-ping Tang; Hai-yan Liu (2011). "Influence of Mg5Ga2 compound on microstructures and electrochemical properties of Mg-5%Hg-22%Ga alloy". Progress in Natural Science: Materials International. 21 (1): 73–79. doi:10.1016/S1002-0071(12)60028-8.

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