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Gadolinium

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Gadolinium
Gadolinium
General Info
Atomic Symbol Gd
Atomic Number 64
Atomic Weight 157.25 g/mol157.25 amu
Chemical series Lanthanides
Appearance silvery white
Gadolinium sample.jpg
Group, Period, Block n/a, 6, f
Electron configuration [Xe] 4f7 5d1 6s2
Electrons per shell 2, 8, 18, 25, 9, 2
CAS number
Physical properties
Phase solid
Density 7.9 g/ml
Melting point 1313°C1,586.15 K
2,395.4 °F
2,855.07 °R
Boiling point 3273°C3,546.15 K
5,923.4 °F
6,383.07 °R
Isotopes of Gadolinium
iso NA half-life DT DE (MeV) DP
152Gd 0.20% 1.08x1014 y α 2.205 148Sm
154Gd 2.18% 154Gd is stable with 90 neutrons.
155Gd 14.80% 155Gd is stable with 91 neutrons.
156Gd 20.47% 156Gd is stable with 92 neutrons.
157Gd 15.65% 157Gd is stable with 93 neutrons.
158Gd 24.84% 158Gd is stable with 94 neutrons.
160Gd 21.86% >1.3x1021 y β−β− 1.7 160Dy
All properties are for STP unless otherwise stated.

Gadolinium is a chemical element not a free element, meaning it does not exist in nature all by itself. It was originally found in a black stone called Cerite that was discovered by Johan Gadolin after which the element was eventually named.[1] Nearly a century later, the last element in the rock was finally identified by a chemist named Jean-Charles Galissard de Marignac. This new-found element was identified as Samaria, however Marignac found that it was not a singe element but two elements bound together. He named one samaria and the other gadolinia. He later found that he was right about gadolinia but incorrect about samaria.[2]

Contents

Properties

Gadollinium

Gadolinium is a silvery-white rare earth metal with malleable and ductile properties. In its alpha form, its hexagonal crystals are tightly packed at room temperature. The alpha form of Gadolinium transforms into its beta form at 1235.oC [3] Gadolinium, out of all the elements, has the highest known thermal neutron capture cross-section at 49,000 barns. A barn is a measurement of an area equal to E-24 cm2. The boiling point of Gadolinium is 3273oC. The boiling point of any element can be found by finding the temperature at which the pressure of the vapor is equal to, or a little bit greater than the pressure of the atmosphere in the environment. [4]

Referring to the graph on the side, a half life is defined as follows: half-life is the period of time it takes for a substance undergoing decay to decrease by half. The name originally was used to describe a characteristic of unstable atoms (radioactive decay), but may apply to any quantity which follows a set-rate decay.

Occurrences

Gadollinium, a rare earth metal

Gadolinium, a natural occurring element, never exists as a free element but is usually found in minerals such as monazite or bastnasite. Gadolinium is also found in gadolonite, but in such small traces that scientists usually get gadolinium through ion exchange and solvent extraction techniques.

Uses

Single photon-emission computed tomography

Gadolinium can be used for a few different things. When combined with other elements Gadolinium can be used for a few different things or it can improve their properties. When alloyed with either iron or chromium, it improves their workability and makes them more resistant to higher temperatures and oxidation.[5]You only need about 1% of gadolinium to improve these things. Also concerning the T.V. you love and adore, when gadolinium forms compounds with phosphor, it is used for the color in your television. Some other compounds of gadolinium, like gadolinium ethyl sulfate, can be used to reduce noise and is sometimes used in MASER, a performance amplifier. At its Curie temperature, which is just above the temperature ferromagnetism vanishes, or just above room tempature, means that this rare metal can be used to sense hot and cold through magnetism.[6] Ferromagnetism is when an metal gets magnetized in a magnetic field, and when the field is removed, it is still magnetized. The computer you are on right now needs gadolinium also; the computer chips need gadolinium which can also be used to manufacture some compact disks. Gadolinium is also used in medical imaging, such as the MRI and MRA scans, X-rays, and PET or Positron Emission Tomogrophy studies. All of these are important uses and should not be taken for granted. [7]

Drawbacks

Some of the drawbacks to Gadolinium can be fatal. When using gadolinium in a MRI/MRA scan, patients with bad kidneys are at risk for a debilitating disease called NSF. NSF, or Nephrogenic Systemic Fibrosis, is a disease that causes patients who have developed large areas of hardened skin with slightly raised plaques, papules, or confluent papules; with or without pigmentary alteration and/or with biopsies showing increased numbers of fibroblasts, alteration of the normal pattern of collagen bundles seen in the dermis, and often increased dermal deposits of mucin. To date, NSF has only occurred in patients with kidney disease. This affects males and females of all ages, but it is most prominent in the middle aged. People with NSF show symptoms of tightening skin, sore muscles, skin thickening, along with sore joints. In severe cases some may be unable to walk or fully extend their limbs. There are many treatments for this disease, yet no cure has been found. Some of the many treatments include: Oral steroids (prednisone), Topical Dovonex (under occlusion), Extracorporeal photopheresis (ECP), Plasmapheresis, Cytoxan, Thalidomide, Ultraviolet therapy, Physical therapy (PT), Pentoxifylline (PXF), High Dose Intravenous Ig Therapy, and Renal transplantation. All of these have shown improvement on patients except for Cytoxan, Thalidomide, and Ultraviolet therapy. [8]

References

  1. History of Gadolinium Unknown, PH Law Firm, 12-10-07.
  2. Gadolinium Summary Unknown, Thomson Gale, a division of Thomson Learning, Inc.,Accessed On-line 12-2-10.
  3. Gadolinium Unknown author, Los Alamos National Laboratory's Chemistry Division, Last updated 12/15/2003
  4. Periodic Table of Elements - Sorted by Cross Section (Thermal Neutron Capture) by Kenneth Barbalace. EnvironmentalChemistry.com. 1995 - 2010. Accessed on-line: 11/22/2010
  5. Its Elemental by Thomas Jefferson National Accelerator Facility - Office of Science Education, Accessed on-line: 11-29-10
  6. Gadolinium Unknown author, Los Alamos National Laboratory's Chemistry Division, Last updated 12/15/2003
  7. Description of GadoliniumUnknown author, Vectorvision, 2004-2010
  8. Official site of the Nephrogenic Systemic FirbrosisShawn Cowper, SE. Nephrogenic Fibrosing Dermopathy [ICNSFR Website], 2001-2009. Available at http://www.icnsfr.org. Accessed 12/01/2010.


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