Tellurium is a chemical element wi seembol Te an atomic nummer 52. A brickle, mildly toxic, rare, siller-white metalloid that looks seemilar tae tin , tellurium is chemically relatit tae selenium an sulphur . It is occasionally foond in native furm, as elemental crystals. Tellurium is far mair common in the universe as a hale nor it is on Yird. Its extreme rarity in the Yird's crust, comparable tae that o platinum , is pairtly due tae its heich atomic nummer, but it's forbye due tae its furmation o a volatile hydride that caused the element tae be lost tae space as a gas in the het nebular formation o the planet.
Quick Facts Pronunciation, Appearance ...
Tellurium, 52 Te Tellurium Pronunciation (tih-LEWR -ee-əm ) Appearance sillery lustrous gray Standard atomic weight A r, std (Te)7002127600000000000♠ 127.60(3)[1] Tellurium in the periodic cairt
Atomic nummer (Z ) 52 Group group 16 (chalcogens) Period period 5 Block p-block Element category Metalloid Electron confeeguration [ Kr ] 4d10 5s2 5p4 Electrons per shell 2, 8, 18, 18, 6 Pheesical properties Phase at STP solit Meltin pynt 722.66 K (449.51 °C, 841.12 °F) Bylin pynt 1261 K (988 °C, 1810 °F) Density (near r.t. ) 6.24 g/cm3 when liquid (at m.p. ) 5.70 g/cm3 Heat o fusion 17.49 kJ/mol Heat o vapourisation 114.1 kJ/mol Molar heat capacity 25.73 J/(mol·K) Vapour pressur
P (Pa)
1
10
100
1 k
10 k
100 k
at T (K)
(775)
(888)
1042
1266
Atomic properties Oxidation states −2 , −1, +1, +2 , +3, +4 , +5, +6 (a mildly acidic oxide)Electronegativity Pauling scale: 2.1 Atomic radius empirical: 140 pm Covalent radius 138±4 pm Van der Waals radius 206 pm Colour lines in a spectral range Spectral lines o telluriumIther properties Naitural occurrence primordial Creestal structur hexagonal [2] Speed o soond thin rod 2610 m/s (at 20 °C) Thermal conductivity (1.97– 3.38) W/(m·K) Magnetic orderin diamagnetic [3] Young's modulus 43 GPa Shear modulus 16 GPa Bulk modulus 65 GPa Mohs haurdness 2.25 Brinell haurdness 180 MPa CAS Nummer 13494-80-9 History Diskivery Franz-Joseph Müller von Reichenstein (1782)First isolation Martin Heinrich Klaproth Main isotopes o tellurium
Iso tope
Abun dance
Hauf-life (t 1/2 )
Decay mode
Pro duct
120 Te
0.09%
>2.2× 1016 y
(β+ β+ )
120 Sn
121 Te
syn
16.78 d
ε
121 Sb
122 Te
2.55%
-
(SF )
123 Te
0.89%
>5× 1019 y
(ε )
123 Sb
124 Te
4.74%
-
(SF )
125 Te
7.07%
-
(SF )
126 Te
18.84%
-
(SF )
127 Te
syn
9.35 h
β−
127 I
128 Te
31.74%
2.2× 1024 y
β− β−
128 Xe
129 Te
syn
69.6 min
β−
129 I
130 Te
34.08%
7.9× 1020 y
β− β−
130 Xe
Decay modes in parentheses are predictit, but hae nae yet been observed | references
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