Calcium Phosphide (Properties, Uses)

Calcium phosphide (CP) is a chemical used in incendiary bombs that comes in the form of a red-brown crystalline powder or grey lumps with a melting temperature of 1600 degrees Celsius. It might take the form of reddish-brown crystals or gray granular masses. Calcium hydroxide and phosphine, a flammable toxic gas, are formed when it combines with water. It is one of the numerous calcium phosphides with the formula Ca3P2, and is defined as a salt-like substance made up of Ca2+ and P3-.

Ca3P2 is the chemical formula for calcium phosphide, which has a molecular weight of 182.1825 g/mol. Photophor is the brand name for the incendiary version, while Polythanol is the brand name for the rodenticide version. It has the CAS number 1305-99-3. It’s a crystalline red-brown substance with a melting point of 1605°C. It has a density of 2.51 grams per cubic centimeter. It quickly forms phosphine, PH3, when combined with water, but is insoluble in ethanol.

When phosphorus comes into contact with air, it usually ignites spontaneously. This phosphine fire will not generally ignite surrounding flammable material if there is an overabundance of water. CaP, CaP3, Ca2P2, and Ca5P8 are some of the more unusual calcium phosphides. It’s simple to make by combining metal with red phosphorus at a high temperature. The optimum method is to sublime P4 in an inert gas stream at 450°C and then react it with Mg metal at 750°C.

Structure of calcium phosphide

Ca3P2 appears as a reddish-brown crystalline powder or grey lumps. Photophor is the brand name for the incendiary version, while Polytanol is the brand name for the rodenticide version. Calcium phosphide is a reddish-brown crystalline solid with gray granules. It has a musty stench that reminds me of acetylene. It may be made by chemical reactions, although carbothermal reduction of calcium phosphate is the most frequent method:

Ca3(PO4)2 + 8 C → Ca3P2 + 8 CO

X-ray crystallography has not established the structure of Ca3P2 in its room temperature state. Rietveld refinement has been used to describe a high-temperature phase. The Ca2+ centers are octahedral in shape. Bypassing phosphorus fumes over metallic calcium while heating calcium phosphate with aluminum or carbon. Due to phosphde, which releases phosphine in the presence of moisture, it is extremely poisonous. The phosphine may spontaneously ignite in the air. At 300°C, an incandescent reaction with oxygen occurs. Dichlorine oxide is incompatible.

Metal phosphides have been used to kill rats in the past. The rats are given a combination of food and calcium phosphide to consume. The poisonous phosphine gas is produced when the acid in the rodent’s digestive system interacts with the phosphide. The substance produces phosphine, which is poisonous and easily ignited when it comes into contact with acids or water. The interaction of phosphine with metals or their salts can produce several phosphides. Electrothermal reduction of metal oxides in the presence of carbon and phosphates can also yield metallic phosphides.

Fireworks, torpedoes, self-igniting naval pyrotechnic flares, and different water-activated munitions all include calcium phosphide. External contact with dust produces irritation of the eyes and skin; inhalation or ingestion causes faintness, weakness, nausea, and vomiting; external contact with dust causes irritation of the eyes and skin. Strong bases, strong acids, oxoacids, epoxides, chlorine monoxide, halogens, halogen acids, oxygen, and sulfur should all be avoided.

Charles Kingsford Smith employed separate buoyant canisters of calcium carbide and calcium phosphide as naval flares that lasted up to 10 minutes throughout the 1920s and 1930s. Some ancient Greek fire formulae may have included calcium phosphide, which was created by boiling bones in urine in a closed vessel. The odor of calcium phosphide baits is strong and unpleasant, similar to that of phosphine produced by hydrolysis. The odor attracts rats but repels other creatures that aren’t attracted to it. Incendiary bombs and other explosives employ this salt.

Calcium phosphide is a frequent contaminant in calcium carbide, and the phosphine-contaminated acetylene it produces can spontaneously burn. Calcium phosphide releases phosphine when it comes into contact with acids or water. Fireworks, torpedoes, self-igniting naval pyrotechnic flares and different water-activated munitions all employ it.

Information Sources:

  4. wikipedia