Report.familyIIIB (Compatability Mode)

8/8/2019 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

Documents

Report.familyIIIB (Compatability Mode)