Tellurium

Tellurium,  ₅₂Te

General properties
Name, seembol	tellurium, Te
Appearance	sillery lustrous gray
Pronunciation	/tᵻˈlʲʊəriəm/ te-LEWR-ee-əm
Tellurium in the periodic cairt
Se ↑ Te ↓ Po antimony ← tellurium → iodine
Atomic nummer (Z)	52
Group, block	group 16 (chalcogens), p-block
Period	period 5
Element category	metalloid
Staundart atomic wicht (Ar)	127.60
Electron configuration	[Kr] 4d10 5s2 5p4
per shell	2, 8, 18, 18, 6
Pheesical properties
Phase	solid
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	6, 5, 4, 2, -2 (mildly acidic oxide)
Electronegativity	Pauling scale: 2.1
Atomic radius	empirical: 140 pm
Covalent radius	138±4 pm
Van der Waals radius	206 pm
Miscellanea
Crystal structur	​hexagonal
Speed o soond thin rod	2610 m/s (at 20 °C)
Thermal conductivity	(1.97–3.38) W/(m·K)
Magnetic orderin	diamagnetic
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
Discovery	Franz-Joseph Müller von Reichenstein (1782)
First isolation	Martin Heinrich Klaproth
Maist stable isotopes o tellurium
iso NA hauf-life DM DE (MeV) DP 120Te 0.09% >2.2×1016 y (β+β+) 1.701 120Sn 121Te syn 16.78 d ε 1.040 121Sb 122Te 2.55% - (SF) <30.974 123Te 0.89% >5×1019 y (ε) 0.051 123Sb 124Te 4.74% - (SF) <28.221 125Te 7.07% - (SF) <26.966 126Te 18.84% - (SF) <26.011 127Te syn 9.35 h β− 0.698 127I 128Te 31.74% 2.2×1024 y β−β− 0.867 128Xe 129Te syn 69.6 min β− 1.498 129I 130Te 34.08% 7.9×1020 y β−β− 2.528 130Xe
Decay modes in parentheses are predictit, but hae nae yet been observed

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.