Thallium

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Thallium,  81Tl
Thallium pieces in ampoule.jpg
General properties
Appearance sillery white
Staundart atomic wecht (Ar, staundart) [204.382204.385] conventional: 204.38
Thallium in the periodic cairt
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Airn Cobalt Nickel Capper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Siller (element) Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercur (element) Thallium Leid (element) Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Ununtrium Flerovium Ununpentium Livermorium Ununseptium Ununoctium
In

Tl

Uut
mercurthalliumlead
Atomic nummer (Z) 81
Group group 13 (boron group)
Period period 6
Element category   post-transition metal
Block p-block
Electron confeeguration [Xe] 4f14 5d10 6s2 6p1
Electrons per shell
2, 8, 18, 32, 18, 3
Pheesical properties
Phase (at STP) solit
Meltin pynt 577 K ​(304 °C, ​579 °F)
Bylin pynt 1746 K ​(1473 °C, ​2683 °F)
Density (near r.t.) 11.85 g/cm3
when liquid (at m.p.) 11.22 g/cm3
Heat o fusion 4.14 kJ/mol
Heat o vapourisation 165 kJ/mol
Molar heat capacity 26.32 J/(mol·K)
Vapour pressur
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 882 977 1097 1252 1461 1758
Atomic properties
Oxidation states

3, 2, 1

(mildly basic oxide)
Electronegativity Pauling scale: 1.62
Atomic radius empirical: 170 pm
Covalent radius 145±7 pm
Van der Waals radius 196 pm
Color lines in a spectral range
Miscellanea
Creestal structurhexagonal close-packed (hcp)
Hexagonal close packed creestal structur for thallium
Speed o soond thin rod 818 m/s (at 20 °C)
Thermal expansion 29.9 µm/(m·K) (at 25 °C)
Thermal conductivity 46.1 W/(m·K)
Electrical resistivity 0.18 µ Ω·m (at 20 °C)
Magnetic orderin diamagnetic[1]
Young's modulus 8 GPa
Shear modulus 2.8 GPa
Bouk modulus 43 GPa
Poisson ratio 0.45
Mohs haurdness 1.2
Brinell haurdness 26.4 MPa
CAS Nummer 7440-28-0
History
Diskivery William Crookes (1861)
First isolation Claude-Auguste Lamy (1862)
Main isotopes o thallium
Iso­tope Abun­dance Hauf-life (t1/2) Decay mode Pro­duct
203Tl 29.524% - (α) 199Au
204Tl syn 3.78 y β 204Pb
ε 204Hg
205Tl 70.476% - (α) 201Au
Decay modes in parentheses are predictit, but hae nae yet been observed
| references | in Wikidata

Thallium is a chemical element wi seembol Tl an atomic nummer 81. This saft gray poor metal is nae foond free in naitur. When isolated, it resembles tin, but discolors when exposed tae air. Chemists William Crookes an Claude-Auguste Lamy discovered thallium independently in 1861, in residues o sulfuric acid production. Baith uised the newly developed method o flame spectroscopy, in which thallium produces a notable green spectral line. Thallium, frae Greek θαλλός, thallos, meanin "a green shuit or twig," wis named bi Crookes. It wis isolatit bi electrolysis a year later, bi Lamy.

References[eedit | eedit soorce]

  1. Magnetic susceptibility of the elements and inorganic compounds, in Handbook of Chemistry and Physics 81st edition, CRC press.