Zirconium Zr

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(No Transcript)
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Pure Zirconium
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Zirconium Oxide
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History

• Zirconium minerals have been around for a long
  time but have been known as either jargon,
  jacinth, and hyacinth
• Martin Henrich Klaproth who lived between 1742
  and 1817, isolated the oxide of zirconium from
  zircon in 1789
• Zirconium is 25 silica, 5 iron oxide, and 70
  zirconia.
• Metallic zirconium was first prepared in 1824
  by Jons J. Berzelius, a Swedish chemist.
• The zirconium-containing mineral zircon, or its
  variations (jargon, hyacinth, jacinth, or
  ligure), were mentioned in biblical writings
• The mineral was not known to contain a new
  element until Klaproth analyzed a jargon from
  the island of Ceylon in the Indian Ocean
• Pure zirconium wasn't prepared until 1914.

Jons J. Berzelium
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Appearance
A lustrous, very corrosion resistant, gray-white,
strong transition metal that resembles titanium,
zirconium is obtained mainly from the mineral
zircon.
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Characteristics

• Zirconium is lighter than steel and its hardness
  is the same as copper. When it is finely divided
  into a powder, zirconium can spontaneously ignite
  in air, especially at high temperatures. The
  Zirconium-zinc alloy becomes magnetic at
  temperatures below 35K. The oxidation state of
  zirconium is usually 4, although 3 and 2 can
  also be obtained in chemical compounds.
• Zirconium is one of the more abundant elements,
  and is widely distributed in the Earth's crust.
  Being very reactive chemically, it is found only
  in the combined state. Under most conditions, it
  bonds with oxygen in preference to any other
  element, and it occurs in the Earth's crust only
  as the oxide, ZrO2 or as part of a complex of
  oxides as in zircon, elpidite, and eudialyte.
• Melting point 1852C
• Boiling point 4409C
• Density 6.52g cm-3

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Uses

• Zirconium is primarily used in nuclear reactors,
  especially in the cladding of the fuel rods, due
  to its low neutron-capture cross-section and its
  resistance to corrosion.
• Zirconium is marketed as a natural gemstone used
  in jewellery.
• Zirconium oxide is processed to produce cubic
  zirconia. This forms a brilliant clear crystal
  used as a low-cost substitute for diamond.
• Most of the zirconium used has been as compounds
  for the ceramic industry refractory, glazes,
  enamels, foundry mold and core washes, abrasive
  grits, and components of electrical ceramics, The
  incorporation of zirconium oxide in glass
  significantly increases its resistance to alkali.
  Another significant use has been in photo
  flashbulbs.

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Reactions

• Reaction of zirconium with air
• Zirconium metal is coated with an oxide layer
  that usually renders it inactive. However
  zirconium does burn in air if provoked to form
  thedioxide zirconium(IV) oxide, ZrO2.
• Zr(s) O2(g) ? ZrO2(s)
• Reaction of zirconium with water
• Zirconium does not react with water under normal
  conditions.
• Reaction of zirconium with the halogens
• Zirconium does react with the halogens upon
  warming to form zirconium(IV) halides. So,
  zirconium reacts with fluorine, F2, chlorine,
  Cl2, bromine, I2, and iodine, I2, to form
  respectively zirconium(IV) bromide, ZrF4,
  zirconium(IV) chloride, ZrCl4, zirconium(IV)
  bromide, ZrBr4, and zirconium(IV) iodide, ZrI4.
• Zr(s) 2F2(g) ? ZrF4(s) white
• Zr(s) 2Cl2(g) ? ZrCl4(l) white
• Zr(s) 2Br2(g) ? ZrBr4(s) white
• Zr(s) 2I2(g) ? ZrI4(s) white
• Reaction of zirconium with acids
• Zirconium metal is coated with an oxide layer
  that usually renders it inactive. Most cold
  mineral acids have little effect. Zirconium does
  dissolve in hydrofluoric acid, HF, presumably to
  form fluoro complexes.
• Reaction of zirconium with bases
• Zirconium does not appear to react with alkalis
  under normal conditions, even when hot.

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Cubic Zirconium

• Cubic Zirconia is well known as a substitute for
  diamond, due to its high hardness and great
  fire. 
• CZ is a beautiful synthetic gemstone that is
  durable and inexpensive and now even comes in any
  color of the rainbow
• Cubic Zirconia is a cubic form of zirconium oxide
  that is created in a laboratory, thus it is not a
  mineral.  However, it was found naturally
  occurring once at one site in the 1930's, but has
  yet to be discovered since then.    
• Cubic Zirconia is an oxide of the metallic
  element zirconium, ZrO2.  Each zirconium atom is
  surrounded by eight oxygen atoms and each oxygen
  atom is connected to four zirconium atoms.
   Mostly all CZ on the market also contains
  yttrium oxide that acts as a stabilizer.  In
  colored CZ, other oxides are added to produce the
  colors.  Most CZ is about 87.5 zirconium oxide
  and 12.5 yttrium oxide.  Though these compounds
  are both opaque, white ores, they melt together
  to form an amazing clear crystal.
• To produce CZ, ZrO2 is heated to about 2300
  degrees Celsius. This causes the mineral to
  become isometric. However, this change is not
  permanent, it reverses upon cooling which is why
  a stabilizer must be added to prevent
  transformation upon cooling. If too much
  stabilizer is added, it results in a softer, less
  brilliant product. This requires such high heat
  that a special radio frequency "skull crucible"
  must be used to melt the zirconia powder. As the
  zirconia melts, it leaves a thin shell that
  remains  solid because it is cooled by the water
  in the copper fingers. As this occurs the
  zirconia and the stabilizing oxide are added to
  fill the skull the desired level. The contents
  are kept molten for several hours to ensure
  uniformity. To produce colors, oxides of cerium,
  copper, titanium, iron, nickel, and many other
  elements are added also.