Cm Curium
Element Information, Facts, Properties, Trends, Uses, Comparison with other elements

Curium is a transuranic radioactive chemical element with symbol Cm and atomic number 96. This element of the Actinide series was named after Marie and Pierre Curie – both were known for their research on radioactivity. Curium was first intentionally produced and identified in July 1944 by the group of Glenn T. Seaborg at the University of California, Berkeley.
It belongs to group of the periodic table having trivial name .
Curium Facts
Read key information and facts about element Curium
Name | Curium |
Atomic Number | 96 |
Atomic Symbol | Cm |
Atomic Weight | 247 |
Phase | Solid |
Color | Silver |
Appearance | silvery metallic, glows purple in the dark |
Classification | Actinide |
Group in Periodic Table | - |
Group Name | |
Period in Periodic Table | period 7 |
Block in Periodic Table | f -block |
Electronic Configuration | [Rn] 5f7 6d1 7s2 |
Electronic Shell Structure (Electrons per shell) | 2, 8, 18, 32, 25, 9, 2 |
Melting Point | 1618 K |
Boiling Point | 3383 K |
CAS Number | CAS7440-51-9 |
How to Locate Curium on Periodic Table
Periodic table is arranged by atomic number, number of protons in the nucleus which is same as number of electrons. The atomic number increases from left to right. Periodic table starts at top left ( Atomic number 1) and ends at bottom right (atomic number 118). Therefore you can directly look for atomic number 96 to find Curium on periodic table.
Another way to read periodic table and locate an element is by using group number (column) and period number (row). To locate Curium on periodic table look for cross section of group - and period 7 in the modern periodic table.
Curium History
The element Curium was discovered by G. T. Seaborg, R. A. James and A. Ghiorso in year 1944 in United States. Curium was first isolated by in . Curium derived its name from Pierre Curie, a physicist, and Marie Curie, a physicist and chemist, named after great scientists by analogy with gadolinium.
Prepared by bombarding plutonium with alpha particles during the Manhattan Project
Curium Presence: Abundance in Nature and Around Us
The table below shows the abundance of Curium in Universe, Sun, Meteorites, Earth's Crust, Oceans and Human Body.
ppb by weight (1ppb =10^-7 %) | ppb by atoms (1ppb =10^-7 %) | |
---|---|---|
Abundance in Universe | - | - |
Abundance in Sun | - | - |
Abundance in Meteorites | - | - |
Abundance in Earth's Crust | - | - |
Abundance in Oceans | - | - |
Abundance in Humans | - | - |
Crystal Structure of Curium
The solid state structure of Curium is Simple Hexagonal.
The Crystal structure can be described in terms of its unit Cell. The unit Cells repeats itself in three dimensional space to form the structure.
Unit Cell Parameters
The unit cell is represented in terms of its lattice parameters, which are the lengths of the cell edges Lattice Constants (a, b and c)
a | b | c |
---|---|---|
349.6 pm | 349.6 pm | 1133.1 pm |
and the angles between them Lattice Angles (alpha, beta and gamma).
alpha | beta | gamma |
---|---|---|
π/2 | π/2 | 2 π/3 |
The positions of the atoms inside the unit cell are described by the set of atomic positions ( xi, yi, zi) measured from a reference lattice point.
The symmetry properties of the crystal are described by the concept of space groups. All possible symmetric arrangements of particles in three-dimensional space are described by the 230 space groups (219 distinct types, or 230 if chiral copies are considered distinct.
Space Group Name | P63/mmc |
Space Group Number | 194 |
Crystal Structure | Simple Hexagonal |
Number of atoms per unit cell |

The number of atoms per unit cell in a simple cubic, face-centered cubic and body-centred cubic are 1,4,2 respectively.
Curium Atomic and Orbital Properties
Curium atoms have 96 electrons and the electronic shell structure is [2, 8, 18, 32, 25, 9, 2] with Atomic Term Symbol (Quantum Numbers) 9D2.
Atomic Number | 96 |
Number of Electrons (with no charge) | 96 |
Number of Protons | 96 |
Mass Number | 247 |
Number of Neutrons | 151 |
Shell structure (Electrons per energy level) | 2, 8, 18, 32, 25, 9, 2 |
Electron Configuration | [Rn] 5f7 6d1 7s2 |
Valence Electrons | 5f7 6d1 7s2 |
Valence (Valency) | 4 |
Main Oxidation States | 3 |
Oxidation States | 3, 4, 5, 6 |
Atomic Term Symbol (Quantum Numbers) | 9D2 |
Bohr Atomic Model of Curium - Electrons per energy level

n | s | p | d | f |
---|
Ground State Electronic Configuration of Curium - neutral Curium atom
Abbreviated electronic configuration of Curium
The ground state abbreviated electronic configuration of Neutral Curium atom is [Rn] 5f7 6d1 7s2. The portion of Curium configuration that is equivalent to the noble gas of the preceding period, is abbreviated as [Rn]. For atoms with many electrons, this notation can become lengthy and so an abbreviated notation is used. This is important as it is the Valence electrons 5f7 6d1 7s2, electrons in the outermost shell that determine the chemical properties of the element.
Unabbreviated electronic configuration of neutral Curium
Complete ground state electronic configuration for the Curium atom, Unabbreviated electronic configuration
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d10 6s2 6p6 5f7 6d1 7s2
Electrons are filled in atomic orbitals as per the order determined by the Aufbau principle, Pauli Exclusion Principle and Hund’s Rule.

Atomic Structure of Curium
Curium atomic radius is - , while it's covalent radius is - .
Atomic Radius Calculated | - (0 Å) |
Atomic Radius Empirical | 176 pm (1.76 Å) |
Atomic Volume | 18.05 cm3/mol |
Covalent Radius | - |
Van der Waals Radius | - |
Neutron Cross Section | 60 |
Neutron Mass Absorption | - |
Atomic Spectrum of Curium
Curium Chemical Properties: Curium Ionization Energies and electron affinity
The electron affinity of Curium is - .
Valence | 4 |
Electronegativity | 1.28 |
ElectronAffinity | - |
Ionization Energy of Curium
Refer to table below for Ionization energies of Curium
Ionization energy number | Enthalpy - kJ/mol |
---|---|
1st | 581 |
Curium Physical Properties
Refer to below table for Curium Physical Properties
Density | 13.51 g/cm3 |
Molar Volume | 18.05 cm3/mol |
Elastic Properties
Young Modulus | - |
Shear Modulus | - |
Bulk Modulus | - |
Poisson Ratio | - |
Hardness of Curium - Tests to Measure of Hardness of Element
Mohs Hardness | - |
Vickers Hardness | - |
Brinell Hardness | - |
Curium Electrical Properties
Curium is Conductor of electricity. Refer to table below for the Electrical properties ofCurium
Electrical Conductivity | - |
Resistivity | - |
Superconducting Point | - |
Curium Heat and Conduction Properties
Thermal Conductivity | - |
Thermal Expansion | - |
Curium Magnetic Properties
Magnetic Type | - |
Curie Point | - |
Mass Magnetic Susceptibility | - |
Molar Magnetic Susceptibility | - |
Volume Magnetic Susceptibility | - |
Optical Properties of Curium
Refractive Index | - |
Acoustic Properties of Curium
Speed of Sound | - |
Curium Thermal Properties - Enthalpies and thermodynamics
Refer to table below for Thermal properties of Curium
Melting Point | 1618 K (1344.85°C, 2452.73 °F) |
Boiling Point | 3383 K (3109.85°C, 5629.73 °F) |
Critical Temperature | - |
Superconducting Point | - |
Enthalpies of Curium
Heat of Fusion | - |
Heat of Vaporization | - |
Heat of Combustion | - |
Curium Isotopes - Nuclear Properties of Curium
Curium has 20 isotopes, with between 233 and 252 nucleons. Curium has 0 stable naturally occuring isotopes.
Isotopes of Curium - Naturally occurring stable Isotopes: -.
Isotope | Z | N | Isotope Mass | % Abundance | T half | Decay Mode |
---|---|---|---|---|---|---|
233Cm | 96 | 137 | 233 | Synthetic | ||
234Cm | 96 | 138 | 234 | Synthetic | ||
235Cm | 96 | 139 | 235 | Synthetic | ||
236Cm | 96 | 140 | 236 | Synthetic | ||
237Cm | 96 | 141 | 237 | Synthetic | ||
238Cm | 96 | 142 | 238 | Synthetic | ||
239Cm | 96 | 143 | 239 | Synthetic | ||
240Cm | 96 | 144 | 240 | Synthetic | ||
241Cm | 96 | 145 | 241 | Synthetic | ||
242Cm | 96 | 146 | 242 | Synthetic | ||
243Cm | 96 | 147 | 243 | Synthetic | ||
244Cm | 96 | 148 | 244 | Synthetic | ||
245Cm | 96 | 149 | 245 | Synthetic | ||
246Cm | 96 | 150 | 246 | Synthetic | ||
247Cm | 96 | 151 | 247 | Synthetic | 1.56×10^7 years | AlphaEmission |
248Cm | 96 | 152 | 248 | Synthetic | ||
249Cm | 96 | 153 | 249 | Synthetic | ||
250Cm | 96 | 154 | 250 | Synthetic | ||
251Cm | 96 | 155 | 251 | Synthetic | ||
252Cm | 96 | 156 | 252 | Synthetic |
Regulatory and Health - Health and Safety Parameters and Guidelines
Database Search
List of unique identifiers to search the element in various chemical registry databases
Database | Identifier number |
---|---|
CAS Number - Chemical Abstracts Service (CAS) | CAS7440-51-9 |
RTECS Number | - |
CID Number | - |
Gmelin Number | - |
NSC Number | - |
Compare Curium with other elements
Compare Curium with all Group elements
Compare Curium with all Period 7 elements
Compare Curium with all Actinide elements
FAQs
What is the electronic configuration of Curium?
The electronic configuration of Curium is 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d10 6s2 6p6 5f7 6d1 7s2.
What is the abbreviated electronic configuration of Curium?
The abbreviated electronic configuration of Curium is [Rn] 5f7 6d1 7s2. To form abbreviated notation of electronic configuration, the completely filled subshells are replaced by the noble gas of the preceding period in square brackets.
What is the symbol of Curium?
Symbol of Curium is Cm. Curium is a chemical element with symbol Cm and atomic number 96.
What is the position of Curium in the Periodic Table?
Curium is a chemical element with the symbol Cm and atomic number 96. Curium is the 96 element on the periodic table. It is located in group null and period 7 in the modern periodic table.
What is the atomic number of Curium?
The atomic number of Curium is 96.
What is the color of Curium?
Curium is of Silver color.
Who discovered Curium?
The element Curium was discovered by G. T. Seaborg, R. A. James and A. Ghiorso in year 1944 in United States. Curium was first isolated by undefined in undefined.
How many valence electrons does a Curium atom have?
Curium has 4 valence electrons. Curium has 96 electrons out of which 4 valence electrons are present in the 5f7 6d1 7s2 outer orbitals of atom.
What is the melting Point of Curium?
Melting Point of Curium is 1618 K.
What is the boiling Point of Curium?
Boiling Point of Curium is 3383 K.
What is the melting Point of Curium in Kelvin?
Melting Point of Curium in Kelvin is 1618 K.
What is the boiling Point of Curium in Kelvin?
Boiling Point of Curium in Kelvin is 3383 K.
What is the electronic configuration of Curium 96?
The electronic configuration of Curium will be 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d10 6s2 6p6 5f7 6d1 7s2.
How do you write the electron configuration for Curium?
The electronic configuration of Curium will be 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d10 6s2 6p6 5f7 6d1 7s2.