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White phosphorus was originally made commercially for the match industry in the 19 th century, by distilling off phosphorus vapor from precipitated phosphates, mixed with ground coal or charcoal, [link] . The precipitated phosphates were made from ground-up bones that had been de-greased and treated with strong acids. This process is, however, obsolete due to the submerged-arc furnace for phosphorus production was introduced to reduce phosphate rock. Calcium phosphate (phosphate rock) is heated to 1200 - 1500 °C with SiO 2 and coke (impure carbon) to produce vaporized tetraphosphorus, P 4 .

Physical properties

The physical properties of the Group 15 elements ( [link] ) encompasses a gas (N 2 ), a non-metallic solid (P 4 ), metalloids (As and Sb), and a metal (Bi).

Selected physical properties of the Group 15 elements.
Element Mp (°C) Bp (°C) Density (g/cm 3 )
N -210.00 -195.79 1.251 g/L (0 °C @ 101.325 kPa)
P 44.2 (white), 610 (black) 280.5 (white), 416 - 590 (sub., red), 620 (sub, violet) 1.823 (white), 2.2 - 2.34 (red), 2.36 (violet), 2.69 (black)
As 817 615 (sub.) 5.727
Sb 630.63 1587 6.697 (solid), 6.53 (liquid)
Bi 271.5 1564 9.78 (solid), 10.05 (liquid)

Vapor phase

Nitrogen forms a dimer in the vapor phase with a triple bond ( [link] ). In the vapor phase above 800 °C tetraphosphorus (P 4 ) is partially dissociated to P 2 .

Molecular orbital diagram for the formation of N 2 .

Solid state

Phosphorus forms a number of allotropes with very different properties ( [link] ). Red phosphorus is an intermediate phase between the white and violet forms. Scarlet phosphorus is obtained by allowing a solution of white phosphorus in carbon disulfide to evaporate in sunlight. Black phosphorus is formed by heating white phosphorus under high pressures ( ca . 12,000 atmospheres).

Images of (left to right) white, red, violet and black allotropes of phosphorus.

White phosphorus has two forms, low-temperature β form and high-temperature α form; both of which contain the P4 tetrahedron ( [link] ). White phosphorus is the least stable, the most reactive, most volatile, less dense, and most toxic of the allotropes.

The structure of the P 4 molecule in white phosphorus.

The structural relationship between white and red phosphorus involves breaking one of the P-P bonds in the P 4 unit and forming a bond with a neighboring tetrahedron to give a chain structure ( [link] ). Red phosphorus is formed by heating white phosphorus to 250 °C or by exposing white phosphorus to sunlight. Actually red phosphorus is not a single allotrope, but rather an intermediate phase between the white and violet phosphorus, and most of its properties have a range of values ( [link] ).

Crystal unit cell of red phosphorus.

Violet phosphorus ( [link] ) is the thermodynamic stable form of phosphorus that is produced by heating red phosphorus above 550 °C. Due to the synthesis being developed by Johann Hittorf ( [link] ) it is sometimes known as Hittorf's phosphorus .

Structure of violet (Hittorf’s) phosphorus.
German physicist Johann Wilhelm Hittorf (1824 - 1914).

Black phosphorus is the least reactive allotrope and the thermodynamic stable form below 550 °C. It is also known as β-metallic phosphorus and has a structure somewhat resembling that of graphite ( [link] ).

Crystal structure of black phosphorus.

In a similar manner to phosphorus, arsenic has several allotropes some of which a structurally related to those of phosphorus. Grey arsenic has a structure similar to black phosphorus ( [link] ). Yellow arsenic (As 4 ) is soft and waxy with a structure similar to too P 4 ( [link] ). Finally, black arsenic is similar in structure to red phosphorus ( [link] ). Antimony and bismuth are both traditional metals and have trigonal hexagonal structures ( a = 4.299, c = 11.25 Å, and a = 4.537, c = 11.838 Å, respectively).

Bibliography

  • V. Biringuccio, The Pirotechnia of Vannoccio Biringuccio: The Classic Sixteenth-Century Treatise on Metals and Metallurgy , Dover Publications (1990).

Questions & Answers

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biomolecules are e building blocks of every organics and inorganic materials.
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research.net
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Introduction about quantum dots in nanotechnology
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nano basically means 10^(-9). nanometer is a unit to measure length.
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there is no specific books for beginners but there is book called principle of nanotechnology
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s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
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That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
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Mostly, they use nano carbon for electronics and for materials to be strengthened.
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CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
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Do you know which machine is used to that process?
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of graphene you mean?
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or in general
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Graphene has a hexagonal structure
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Source:  OpenStax, Chemistry of the main group elements. OpenStax CNX. Aug 20, 2010 Download for free at http://cnx.org/content/col11124/1.25
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