General | |||||||||||||||||||||||||
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Name, Symbol, Number | Thallium, Tl, 81 | ||||||||||||||||||||||||
Chemical series | True metals[?] | ||||||||||||||||||||||||
Group, Period, Block | 13 (IIIA)[?], 6 , p | ||||||||||||||||||||||||
Density, Hardness | 11850 kg/m3, 1.2 | ||||||||||||||||||||||||
Appearance | Silvery white | ||||||||||||||||||||||||
Atomic Properties | |||||||||||||||||||||||||
Atomic weight | 204.3833 amu | ||||||||||||||||||||||||
Atomic radius (calc.) | 190 (156) pm | ||||||||||||||||||||||||
Covalent radius | 148 pm | ||||||||||||||||||||||||
van der Waals radius | 196 pm | ||||||||||||||||||||||||
Electron configuration | [Xe]4f14 5d10 6s2 6p1 | ||||||||||||||||||||||||
e- 's per energy level | 2, 8, 18, 32, 18, 3 | ||||||||||||||||||||||||
Oxidation states (Oxide) | 3,1 (mildly basic) | ||||||||||||||||||||||||
Crystal structure | Hexagonal | ||||||||||||||||||||||||
Physical Properties | |||||||||||||||||||||||||
State of matter | solid | ||||||||||||||||||||||||
Melting point | 577 K (579 °F) | ||||||||||||||||||||||||
Boiling point | 1746 K (2683 °F) | ||||||||||||||||||||||||
Molar volume | 17.22 ×10-3 m3/mol | ||||||||||||||||||||||||
Heat of vaporization | 164.1 kJ/mol | ||||||||||||||||||||||||
Heat of fusion | 4.142 kJ/mol | ||||||||||||||||||||||||
Vapor pressure | 5.33 E-06 Pa at 577 K | ||||||||||||||||||||||||
Speed of sound | 818 m/s at 293.15 K | ||||||||||||||||||||||||
Miscellaneous | |||||||||||||||||||||||||
Electronegativity | 1.62 (Pauling scale) | ||||||||||||||||||||||||
Specific heat capacity | 129 J/(kg*K) | ||||||||||||||||||||||||
Electrical conductivity | 6.17 106/m ohm | ||||||||||||||||||||||||
Thermal conductivity | 46.1 W/(m*K) | ||||||||||||||||||||||||
1st ionization potential | 589.4 kJ/mol | ||||||||||||||||||||||||
2nd ionization potential | 1971 kJ/mol | ||||||||||||||||||||||||
3rd ionization potential | 2878 kJ/mol | ||||||||||||||||||||||||
Most Stable Isotopes | |||||||||||||||||||||||||
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SI units & STP are used except where noted. |
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In addition, research activity with thallium is ongoing to develop high-temperature superconducting materials for such applications as magnetic resonance imaging, storage of magnetic energy, magnetic propulsion[?], and electric power generation[?] and transmission. Also, the use of radioactive thallium compounds for medical purposes in cardiovascular imaging to detect heart disease is increasing.
Thallium is found in the minerals crooksite[?], hutchinsonite[?], and lorandite[?]. This metal is also contained in pyrites and is extracted as a by-product of sulfuric acid production when pyrite ore is roasted. Another way this element is obtained is from the smelting of lead and zinc rich ores. Manganese nodules[?] which are found on the ocean floor[?], also contain thallium but nodule extraction is prohibitively expensive and potentially environmentally destructive. In addition, several other thallium minerals containing 16% to 60% thallium, occur in nature as sulfide or selenide complexes with antimony, arsenic, copper, lead, and silver but are rare and have no commercial importance as sources of this element.
The hair loss was the cause of thallium being used in the treatment of ringworm[?], but that use has long been abandoned. There is a persistent story that the CIA, in an attempt to discredit Fidel Castro had actually planned to poison him with thallium so that his beard would fall out, but apparently sanity prevailed and the attempt was never made.
The detective fiction writer, Agatha Christie, who had worked as a pharmacist, used thallium as the agent of murder in her novel The Pale Horse - the first clue to the murder method coming from the hair loss of the victims.
The 1996 film The Young Poisoner's Handbook was based on the activities of Graham Frederick Young[?] who killed at least three people with thallium in the 1960s and 1970s.
wikipedia.org dumped 2003-03-17 with terodump