- Calcium silicide
Section1 = Chembox Identifiers
CASNo = 12013-56-8
Section2 = Chembox Properties
Formula = CaSi2
MolarMass = 96.25
Appearance = whitish grey - black solid
Section3 = Chembox Hazards
Calcium silicide (CaSi2), also called calcium disilicide, is an inorganic compound, a
silicideof calcium. It is a whitish or dark grey to black solid matter with melting point between 700-935°C. It is insoluble in water, but may decompose when subjected to moisture, evolving hydrogenand producing calcium hydroxide. Decomposes in hot water. It is flammable and may ignite spontaneously in air. Its CAS numberis CASREF|CAS=12013-56-8.
Industrial calcium silicide usually contains
ironand aluminiumas the primary contaminants, and low amounts of carbonand sulfur.
Calcium silicide is used for manufacture of special metal
alloys, eg. for removing phosphorusand as a deoxidizer.
pyrotechnics, it is used as fuel to make special mixtures, eg. for production of smokes, in flash compositions, and in percussion caps. Specification for pyrotechnic calcium silicide is MIL-C-324C. In some mixtures it may be substituted with ferrosilicon. Silicon-based fuels are used in some time delay mixtures, eg. for controlling of explosive bolts, hand grenades, and infrared decoys. [http://www.abovetopsecret.com/forum/thread94829/pg1] Smoke compositions often contain hexachloroethane; during burning they produce silicon tetrachloride, which, like titanium tetrachlorideused in smoke-screens, reacts with air moisture and produces dense white fog. Gum arabicis used in some mixtures to inhibit calcium silicide decomposition. [http://groups.google.com/group/rec.pyrotechnics/browse_thread/thread/dc002fbb39b31aeb/63f84b3de3764a8e?lnk=raot] Self-heating cans of military food rations developed during the World War II used a thermite-like mixture of 1:1 iron(II,III) oxideand calcium silicide. Such mixture, when ignited, generates moderate amount of heat and no gaseous products. [http://www.du.edu/~jcalvert/phys/bang.htm]
There is also a calcium silicide CaSi, CAS number CASREF|CAS=12013-55-7. See also CAS number CASREF|CAS=12737-18-7.
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