| Description | Magnesium silicide has the molecular formula of
Mg2Si and the molecular weight of 76.6955 g/mol. Its density is 1.998 g/cc
and its melting point is 1102°C. It is a black powder.
Mg2Si crystallizes in a cubic CaF2 (fluorspar)-type
lattice with a = 4.49 ? . The centers of this lattice are analogous
to that of diamond. Each Si atom forms four covalent
sp3 bonds. The Mg subshells are only half-filled.
There is no bonding between the two Mg atom sites.
The distance between the Mg and Si atoms is 2.77 ? .
Bonding in this compound is essentially covalent.
|
| Chemical Properties | blue crystals |
| Chemical Properties | Magnesium silicide is a slate blue crystalline
solid. |
| Physical properties | Magnesium silicide is unstable in air and reacts with
moisture to form silane. When magnesium silicide is
placed into aqueous HCl, the gas silane, SiH4, is
produced. This gas is the silicon analogue of methane,
CH4, but is more reactive. Silane is pyrophoric, that is
due to the presence of O2 in the air, i.e. it spontaneously
combusts in air.
These reactions are typical of a Group-2 silicide.
Mg2Si reacts similarly with sulfuric acid.
As a powder, magnesium silicide is dark blue or
slightly purple in color. |
| Uses | Magnesium silicide is used to produce alloys such as aluminum alloys. It is also used in food, beverages, as a flavor enhancer and as an intermediate in chemical research. |
| Uses | Magnesium silicide (Mg2Si) can be used as a thermoelectric material for the fabrication of thermoelectric (TE) devices. It can also be used as a counter electrode for lithium-ion batteries. It can generally be synthesized as a nanoparticle that can be utilized as a deoxygenation agent. |
| Uses | In semiconductor research. Has been used to build Mg-Si rectifiers. |
| General Description | A colorless crystalline solid. Insoluble in water and denser than water. Contact may irritate skin, eyes and mucous membranes. May be toxic by ingestion. |
| Air & Water Reactions | Contact with moisture under acidic condition generates silanes that ignite in air. Insoluble in water. |
| Reactivity Profile | MAGNESIUM SILICIDE is a reducing agent. May react vigorously with oxidizing materials. |
| Health Hazard | Inhalation or contact with vapors, substance or decomposition products may cause severe injury or death. May produce corrosive solutions on contact with water. Fire will produce irritating, corrosive and/or toxic gases. Runoff from fire control may cause pollution. |
| Fire Hazard | Produce flammable gases on contact with water. May ignite on contact with water or moist air. Some react vigorously or explosively on contact with water. May be ignited by heat, sparks or flames. May re-ignite after fire is extinguished. Some are transported in highly flammable liquids. Runoff may create fire or explosion hazard. |
| Potential Exposure | Magnesium silicide is used in the
semiconductor industry and to produce certain aluminum
alloys |
| Shipping | UN2624 Magnesium silicide, Hazard Class: 4.3;
Labels: 4.3-Dangerous when wet materia |
| Incompatibilities | Possibly pyrophoric, especially in moist
air. Pyrophoric; mixtures with air are spontaneously explosive. A strong reducing agent. Incompatible with oxidizers
(chlorates, nitrates, peroxides, permanganates, perchlorates,
chlorine, bromine, fluorine, etc.); contact may cause fires
or explosions. Keep away from alkaline materials, mineral
acids, strong acids, strong bases. Reacts with water; releasing explosive hydrogen gas and may also release selfigniting toxic silane gas |
