سېريوم

سېريوم (په انگرېزي: Cerium) له کیمیاوي عناصرو څخه یو دی چې په تناوبي جدول کې د Ce سمبول او ۵۸ اتمي شمېرې په وسیله ښودل شوی دی.

Cerium,  ₅₈Ce

عمومي خواص
Pronunciation	/ˈsɪəriəm/
Appearance	silvery white
Cerium په دوراني جدول کې
– ↑ Ce ↓ Th lanthanum ← cerium → praseodymium ‍
اټومي شمیره (Z)	58
گروپ, پیریود	group n/a, period 6
بلاک	f-block
Element category	lanthanide
معياري اټومي وزن (Ar)	کينډۍ:Val[۱]
Electron configuration	[Xe] 4f1 5d1 6s2[۲]
Electrons per shell	2, 8, 18, 19, 9, 2
فزیکي خواص
حالت (at STP)	جامد
دويلې کيدو ټکى	1068 K ​(795 °C, ​1463 °F)
يشنا ټکی	3716 K ​(3443 °C, ​6229 °F)
Density near r.t.	6.770 g/cm3
when liquid, at m.p.	6.55 g/cm3
Heat of fusion	5.46 kJ/mol
Heat of vaporization	398 kJ/mol
Molar heat capacity	26.94 J/(mol·K)
Vapor pressure P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 1992 2194 2442 2754 3159 3705
اټومي خواص
Oxidation states	4, 3, 2, 1 ​(a mildly basic oxide)
Electronegativity	Pauling scale: 1.12
Ionization energies	1st: 534.4 kJ/mol 2nd: 1050 kJ/mol 3rd: 1949 kJ/mol (more)
Atomic radius	empirical: 181.8 pm
Covalent radius	204±9 pm
Miscellanea
Crystal structure	​double hexagonal close-packed (dhcp) β-Ce
Crystal structure	​face-centered cubic (fcc) γ-Ce
Speed of sound thin rod	2100 m/s (at 20 °C)
Thermal expansion	γ, poly: 6.3 µm/(m·K) (at r.t.)
د تودوخې تېرېدنه	11.3 W/(m·K)
Electrical resistivity	β, poly: 828 nΩ·m (at r.t.)
Magnetic ordering	paramagnetic[۳]
Magnetic susceptibility (χmol)	(β) +2450.0·10−6 cm3/mol (293 K)[۴]
Young's modulus	γ form: 33.6 GPa
Shear modulus	γ form: 13.5 GPa
Bulk modulus	γ form: 21.5 GPa
Poisson ratio	γ form: 0.24
Mohs hardness	2.5
Vickers hardness	210–470 MPa
Brinell hardness	186–412 MPa
CAS Number	7440-45-1
History
Naming	after dwarf planet Ceres, itself named after Roman deity of agriculture Ceres
Discovery	Martin Heinrich Klaproth, Jöns Jakob Berzelius, Wilhelm Hisinger (1803)
First isolation	Carl Gustaf Mosander (1838)
Main isotopes of cerium
آيسو­ټوپ Abun­dance نیم ژوند (t1/2) Decay mode Pro­duct 134Ce syn 3.16 d ε 134La 136Ce 0.186% stable 138Ce 0.251% stable 139Ce syn 137.640 d ε 139La 140Ce 88.449% stable 141Ce syn 32.501 d β− 141Pr 142Ce 11.114% stable 143Ce syn 33.039 d β− 143Pr 144Ce syn 284.893 d β− 144Pr
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