Cadmium

Cadmium,  ₄₈Cd

General properties
Name, seembol	cadmium, Cd
Appearance	sillery bluish-gray metallic
Pronunciation	/ˈkædmiəm/ KAD-mee-əm
Cadmium in the periodic cairt
Zn ↑ Cd ↓ Hg siller ← cadmium → indium
Atomic nummer (Z)	48
Group, block	group 12, d-block
Period	period 5
Element category	transeetion metal, Alternatively considered a post-transeetion metal
Staundart atomic wicht (±) (Ar)	112.414(4)
Electron configuration	[Kr] 4d10 5s2
per shell	2, 8, 18, 18, 2
Pheesical properties
Phase	solid
Meltin pynt	594.22 K ​(321.07 °C, ​609.93 °F)
Bylin pynt	1040 K ​(767 °C, ​1413 °F)
Density near r.t.	8.65 g/cm3
when liquid, at m.p.	7.996 g/cm3
Heat o fusion	6.21 kJ/mol
Heat o vapourisation	99.87 kJ/mol
Molar heat capacity	26.020 J/(mol·K)
vapour pressur P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 530 583 654 745 867 1040
Atomic properties
Oxidation states	2, 1 (mildly basic oxide)
Electronegativity	Pauling scale: 1.69
Atomic radius	empirical: 151 pm
Covalent radius	144±9 pm
Van der Waals radius	158 pm
Miscellanea
Creestal structur	​hexagonal close-packed (hcp)
Speed o soond thin rod	2310 m/s (at 20 °C)
Thermal expansion	30.8 µm/(m·K) (at 25 °C)
Thermal conductivity	96.6 W/(m·K)
Electrical resistivity	(22 °C) 72.7 n Ω·m
Magnetic orderin	diamagnetic
Young's modulus	50 GPa
Shear modulus	19 GPa
Bouk modulus	42 GPa
Poisson ratio	0.30
Mohs haurdness	2.0
Brinell haurdness	203 MPa
CAS Nummer	7440-43-9
History
Diskivery	Karl Samuel Leberecht Hermann an Friedrich Stromeyer (1817)
First isolation	Karl Samuel Leberecht Hermann an Friedrich Stromeyer (1817)
Named bi	Friedrich Stromeyer (1817)
Maist stable isotopes o cadmium
iso NA hauf-life DM DE (MeV) DP 106Cd 1.25% >4.1×1020 y (β+β+) 2.770 106Pd 107Cd syn 6.5 h ε 1.417 107Ag 108Cd 0.89% >4.1×1017 y (β+β+) 0.272 108Pd 109Cd syn 462.6 d ε 0.214 109Ag 110Cd 12.49% - (SF) <22.486 111Cd 12.8% - (SF) <21.883 112Cd 24.13% - (SF) <20.733 113Cd 12.22% 7.7×1015 y β− 0.316 113In 113mCd syn 14.1 y β− 0.580 113In IT 0.264 113Cd 114Cd 28.73% >6.4×1018 y (β−β−) 0.540 114Sn 115Cd syn 53.46 h β− 1.446 115In 116Cd 7.49% 3.1×1019 y β−β− 2.809 116Sn
Decay modes in parentheses are predictit, but hae nae yet been observed

Cadmium is a chemical element wi the seembol Cd an atomic nummer 48. This saft, bluish-white metal is chemically seemilar tae the twa ither stable metals in group 12, zinc an mercur. Lik zinc, it prefers oxidation state +2 in maist o its compoonds an lik mercur it shaws a law meltin pynt compared tae transeetion metals. Cadmium an its congeners are nae always considered transeetion metals, in that thay dae nae hae pairtly filled d or f electron shells in the elemental or common oxidation states. The average concentration o cadmium in the Yird's crust is atween 0.1 an 0.5 pairts per million (ppm). It wis discovered in 1817 simultaneously bi Stromeyer an Hermann, baith in Germany, as an impurity in zinc carbonate.