Phosphide
Encyclopedia
In chemistry, a phosphide is a compound of phosphorus
with a less electronegative
element or elements. Binary compounds are formed with the majority of less electronegative elements with the exception of Hg
, Pb
, Sb
, Bi
, Te, Po
. Typically there are a range of stoichiometries with each element; for example, potassium has nine phosphides (K3P, K4P3, K5P4, KP, K4P6 K3P7, K3P11, KP10.3, KP15) and nickel has eight (Ni3P, Ni5P2, Ni12P5, NiP2, Ni5P4, NiP, NiP2, NiP3).
Classification of these compounds is difficult. On structural and reactivity grounds they can be broadly classified as:
Two polyphosphide ions, P34− found in K4P3 and P45− found in K5P4, are radical anions with an odd number of valence electrons making both compounds paramagnetic.
Phosphorus
Phosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus as a mineral is almost always present in its maximally oxidized state, as inorganic phosphate rocks...
with a less electronegative
Electronegativity
Electronegativity, symbol χ , is a chemical property that describes the tendency of an atom or a functional group to attract electrons towards itself. An atom's electronegativity is affected by both its atomic number and the distance that its valence electrons reside from the charged nucleus...
element or elements. Binary compounds are formed with the majority of less electronegative elements with the exception of Hg
Mercury (element)
Mercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...
, Pb
Lead
Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...
, Sb
Antimony
Antimony is a toxic chemical element with the symbol Sb and an atomic number of 51. A lustrous grey metalloid, it is found in nature mainly as the sulfide mineral stibnite...
, Bi
Bismuth
Bismuth is a chemical element with symbol Bi and atomic number 83. Bismuth, a trivalent poor metal, chemically resembles arsenic and antimony. Elemental bismuth may occur naturally uncombined, although its sulfide and oxide form important commercial ores. The free element is 86% as dense as lead...
, Te, Po
Polonium
Polonium is a chemical element with the symbol Po and atomic number 84, discovered in 1898 by Marie Skłodowska-Curie and Pierre Curie. A rare and highly radioactive element, polonium is chemically similar to bismuth and tellurium, and it occurs in uranium ores. Polonium has been studied for...
. Typically there are a range of stoichiometries with each element; for example, potassium has nine phosphides (K3P, K4P3, K5P4, KP, K4P6 K3P7, K3P11, KP10.3, KP15) and nickel has eight (Ni3P, Ni5P2, Ni12P5, NiP2, Ni5P4, NiP, NiP2, NiP3).
Classification of these compounds is difficult. On structural and reactivity grounds they can be broadly classified as:
- principally ionic with P3
− ions. Examples are the group 1 (e.g. Na3PSodium phosphideSodium phosphide, Na3P, is a black, ionic salt containing the alkali metal sodium and the phosphide anion. Na3P is a source of the highly reactive phosphide anion...
) and group 2 (e.g. Ca3P2Calcium phosphideCalcium phosphide is a chemical is used in incendiary bombs. It has the appearance of red-brown crystalline powder or grey lumps, with melting point of 1600 °C. Its trade name is Photophor for the incendiary use or Polythanol for the use as rodenticide.It may be formed by reaction of the elements...
) metal phosphides. - polyphosphides with, for example, dumbbell P24
− ions; cluster P113− ions; polymeric chain anions (e.g. the helical (P− )n ion) and complex sheet or 3-D anions. - compounds with individual P atoms in a metal lattice that can be semiconducting (e.g. GaP) through to metallic (e.g. TaP) in terms of electrical conductance.
Two polyphosphide ions, P34
Examples
- Aluminium phosphideAluminium phosphideAluminium phosphide is an inorganic compound used as a wide band gap semiconductor and a fumigant. This colourless solid is generally sold as a grey-green-yellow powder due to the presence of impurities arising from hydrolysis and oxidation.-Properties:...
(AlP) - Indium phosphide (InP)
- Calcium phosphideCalcium phosphideCalcium phosphide is a chemical is used in incendiary bombs. It has the appearance of red-brown crystalline powder or grey lumps, with melting point of 1600 °C. Its trade name is Photophor for the incendiary use or Polythanol for the use as rodenticide.It may be formed by reaction of the elements...
(Ca3P2) - Copper phosphide (Cu3P)
- Magnesium phosphide (Mg3P2)