Report.familyIIIB (Compatability Mode)
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Transcript of Report.familyIIIB (Compatability Mode)
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Family
IIIBReported by :
Gongon, Angelo
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Scandium (Sc)
Discovered by: Lars Fredik Nilson in 1879. Eight years
after the Russian Chemist Dmitry Ivanovich Mendeleyev
had predicted, on the basis of the periodic law, that theelement exists in nature and that its properties resemble
those of the element boron.
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Scandium is present in most of the rare earth element
and uranium deposits, but it is extracted from these ores
in only a few mines worldwide. Due to the low availability
and the difficulties in the preparation of metallicscandium, which was first done in 1937, it took until the
1970s before applications for scandium were developed.
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The positive effects of scandium on aluminum alloys
were discovered in the 1970s, and its use in such
alloys remains the only major application of
scandium.
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Application of Scandium
Parts of the Mig29 are madefrom Al-Sc-alloy
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Health and safety
Elemental scandium is not considered to be
toxic. Little animal testing of scandium
compounds has been done.
The median lethal dose(LD50) levels for
scandium(III) chloride for rats have been
determined and were intraperitoneal 4 mg/kg and
oral 755 mg/kg. In the light of these results
compounds of scandium should be handled as
compounds of moderate toxicity.
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Yttrium (Y)
Discovered by: Swedish Chemist Carl Gustav
Mosander in 1843. chemical element with symbol Y and
atomic number 39. It is a silvery-metallic transition metal
chemically similar to the lanthanoids and has historicallybeen classified as a rare earth element.
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Yttrium is almost always found combined with the
lanthanoids in rare earth element and is never found in
nature as a free element. Its only stable isotope, 89Y, is
also its only naturally occurring isotope.
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In 1787, Carl Axel Arrhenius found a new mineral nearYtterby in Sweden and named it ytterbite, after the
village. Johan Gadolin discovered yttrium's oxide in
Arrhenius' sample in 1789, andAnders Gustaf Ekeberg
named the new oxide yttria. Elemental yttrium was firstisolated in 1828 by Friedrich Whler
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The most important use of yttrium is in makingphosphors, such as the red ones used in television
cathode ray tube displays and in LEDs. Other uses
include the production ofelectrodes, electrolytes,
electronic filters, lasers and superconductors; variousmedical applications; and as traces in various materials
to enhance their properties. Yttrium has no known
biological role, but exposure to yttrium compounds can
cause lung disease in humans
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Properties
Yttrium is a soft, silver-metallic, lustrous and highly
crystalline transition metal in group 3. As expected by
periodic trends, it is less electronegative than its
predecessor in the group, scandium, moreelectronegative than its successor in the group,
lanthanum, and less electronegative than the next
member ofperiod 5, zirconium Yttrium is the first d-block
element in the fifth period.
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The pure element is relatively stable in air in bulk form,
due to passivation resulting from the formation of a
protective oxide (Y2O3) film on its surface.
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This film can reach a thickness of 10 m when yttrium is
heated to 750 C in water vapor. When finely divided,
however, yttrium is very unstable in air; shavings or
turnings of the metal can ignite in air at temperatures
exceeding 400 C. Yttrium nitride (YN) is formed when
the metal is heated to 1000 C in nitrogen.
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Yttrium is used in the production of a large variety ofsynthetic garnets, and yttria is used to make yttrium iron
garnets (Y3Fe5O12 orYIG), which are very effective
microwave filters. Yttrium, iron, aluminium, and
gadolinium garnets (e.g. Y3(Fe, Al)5O12 and Y3(Fe,Ga)5O12) have important magnetic properties.
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YIG is also very efficient as an acoustic energytransmitter and transducer. Yttrium aluminium garnet
(Y3Al5O12 orYAG) has a hardness of 8.5 and is also
used as a gemstone in jewelry (simulated diamond).
Cerium-doped yttrium aluminum garnet (YAG:Ce)crystals are used as phosphors to make white LEDs.
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YAG, yttria, yttrium lithium fluoride (LiYF4), and yttrium
orthovanadate (YVO4) are used in combination withdopants such as neodymium, erbium, ytterbium in near-
infrared lasers. YAG lasers have the ability to operate at
high power and are used for drilling into and cutting
metal. The single crystals of doped YAG are normallyproduced by the Czochralski process.
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Medical
The radioactive isotope yttrium-90 is used in drugs such
as Yttrium Y 90-DOTA-tyr3-octreotide and Yttrium Y 90
ibritumomab tiuxetan for the treatment of various
cancers, including lymphoma, leukemia, ovarian,colorectal, pancreatic, and bone cancers. It works by
adhering to monoclonal antibodies, which in turn bind to
cancer cells and kill them via intense -radiation from
the yttrium-90 (see Monoclonal antibody therapy).
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Needles made of yttrium-90, which can cut more
precisely than scalpels, have been used to sever pain-
transmitting nerves in the spinal cord, and yttrium-90 is
also used to carry out radionuclide synovectomy in thetreatment of inflamed joints, especially knees, in
sufferers of conditions such as rheumatoid arthritis.
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A neodymium-doped yttrium-aluminium-garnet laser has
been used in an experimental, robot-assisted radical
prostatectomy in canines in an attempt to reduce
collateral nerve and tissue damage, whilst the erbium-doped ones are starting to be used in cosmetic skin
resurfacing.
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Precautions
1. Water soluble compounds of yttrium are considered
mildly toxic, while its insoluble compounds are non-toxic.
In experiments on animals, yttrium and its compounds
caused lung and liver damage, though toxicity varieswith different yttrium compounds. In rats, inhalation of
yttrium citrate caused pulmonary edema and dyspnea,
while inhalation ofyttrium chloride caused liver edema,
pleural effusions, and pulmonary hyperemia.
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2. Exposure to yttrium compounds in humans may
cause lung disease. Workers exposed to airborneyttrium europium vanadate dust experienced mild eye,
skin, and upper respiratory tract irritationthough this
may have been caused by the vanadium content rather
than the yttrium. Acute exposure to yttrium compoundscan cause shortness of breath, coughing, chest pain,
and cyanosis. NIOSH recommends a time-weighted
average limit of 1 mg/m3 and an IDLH of 500 mg/m3.
Yttrium dust is flammable.
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Example ofYttrium
YAGlaser rod 0.5 cm indiameter