Cm

Curium

Identification

CAS Number: 7440-51-9

Discovery Year: 1944

Discoverer: G.T.Seaborg, R.A.James, A.Ghiorso

Discovery Location: United States

Properties

Atomic Mass: 247 →Density: 13.51 g/cm³ →

Atomic Dimensions

Atomic Radius (Rahm): 276 pm

Covalent Radius: 169 pm →

Van der Waals Radius: 245.00000000000003 pm

Atomic Volume: 18.28 cm³/mol

Thermodynamics

Melting Point: 1340 K →

Heat of Formation: 386 kJ/mol

Electronic Structure

Electron Config: [Rn] 5f7 6d 7s2

Block: f

Period: 7 →

Oxidation States: +3, +4

Abundance & Geochemistry

Goldschmidt Class: synthetic

About

Radioactive metallic transuranic element. Belongs to actinoid series. Nine known isotopes, Cm-247 has a half-life of 1.64*10^7 years. First identified by Glenn T. Seaborg and associates in 1944, first produced by L.B. Werner and I. Perlman in 1947 by bombarding americium-241 with Neutrons. Named for Marie Curie.

Isotopes

Cm-243 243 ☢ 29.1 a

Cm-244 244 ☢ 18.1 a

Cm-245 245 ☢ 8.42e+3 a

Cm-246 246 ☢ 4.71e+3 a

Cm-247 247 ☢ 1.56e+7 a

Cm-248 248 ☢ 3.48e+5 a