A Complete Overview on Curium
When you go through the periodic table in chemistry, you come across various chemical elements of the known universe. This table is divided into several groups, periods, and blocks. The well-organised arrangement is based on the atomic numbers, chemical properties, and electron configuration of these chemical properties.
In the following post, you will learn about one of these elements – curium. This element was identified by an American chemist Glenn T. Seaborg and his colleagues in 1944. The atomic number of curium is 1996, and it is extremely useful in multiple scientific researches. Generally, the production of curium occurs by neutron bombardment of plutonium or uranium in nuclear reactors.
Here are more details about curium. Let’s start learning!
Curium Element
Curium is a synthetic chemical element and one of the elements from actinoid series. It is known to be the 3rd transuranium element discovered yet. Curium is named after the famous French physicist and chemist Pierre Curie and Marie Curie who are regarded as the pioneer of radioactivity. Cm suggests as curium symbol in chemistry.
Initially, curium was obtained by bombarding helium ions on one of the plutonium isotopes – Pt-239. It is a radioactive, chemically active, electro-positive substance that has specific magnetic properties. Its resistivity increases along with the inclining temperature.
Scientists who also involved with Seaborg in the discovery of curium were – Albert Ghiorso, Ralph A. James. These are some vital curium element facts that you must know.
Properties of Curium
As a chemical substance, this metal has some unique properties. Below are some physical and chemical properties of curium.
Physical Properties of Curium
Chemical Properties of Curium
Preparation
The preparation of metallic curium occurs by reducing its components. Primarily, curium (III) fluoride was utilised to produce metallic curium. This specific reaction was initiated in a synthetic environment that is free from oxygen and water. The environment was created inside an apparatus that was composed of tungsten and tantalum. Moreover, lithium or barium was used as reducing agent.
CmF₃ + 3 Li 🡪 Cm + 3 LiF
Another way of obtaining metallic curium is by reduction of curium (IV) oxide. This reaction can be conducted by using zinc-magnesium alloy in a mixture of magnesium fluoride and magnesium chloride.
Compounds of Curium
Oxides
As said earlier, there are four oxidation states of curium available. However, +3 oxidation compounds are mostly found. This metal reacts readily with oxygen and produces (primarily) CmO₂ and Cm₂O₃ oxides. Nonetheless, another divalent oxide CmO can also be found by different reactions.
By burning curium oxalate or (Cm₂(C₂O4)₃ ) and curium nitrate or (Cm(NO₃)₃) in 100% puro oxygen, black coloured CmO2 is produced.
(Cm₂(C₂O4)₃) 🡪 2CmO₂ + 4 CO₂ + 2 C
On further heating at 600 – 650oC in a vacuum, CmO₂ converts into whitish Cm2O₃.
4 CmO₂ 🡪 2 Cm₂O₃ + O₂
Another method of obtaining Cm₂O₃ is by reduction of CmO₂ with the help of molecular hydrogen.
2 CmO₂ + H₂ 🡪 Cm₂O₃ + H₂O
Moreover, some ternary oxides such as M (II) CmO₃ are also found. Here, M suggests a divalent metal like barium.
Also, by thermal oxidation of curium hydride, volatile CmO₂ and CmO₃ are produced as per reports. Curium trioxide or CmO₃ is an example of a +6 oxidation state compound.
Halides
By introducing fluoride ions to curium (III) solutions, colourless curium (III) fluoride or CmF3 can be formed. However, another halide – tetravalent curium (IV) fluoride can only be generated by the reaction between CmF₃ and molecular fluorine.
2 CmF₃ + F₂ 🡪 2 CmF₄
Multiple ternary fluorides can also be created with a generic form of A₇Cm₆F₃₁. Here, A suggests alkali metals.
Curium (III) hydroxide or Cm(OH)₃ reacts with anhydrous hydrogen chloride to produce colourless curium (III) chloride or CmCl₃. Curium (III) chloride can also be transformed into colourless curium (III) iodide and light green to colourless curium (III) bromide. These conversions occur when CmCl₃ reacts with ammonium salt at 400 – 450oC temperature.
Other Compounds
At high temperatures, curium form compounds with the gaseous form of tellurium, selenium, and sulphur. These compounds are tellurides, selenides, and sulphides, respectively. This metal can also create its pnictides as CmX with phosphorus, antimony, arsenic, and nitrogen. Curium pnictides can be formed by the reaction between these elements and metallic curium or curium (III) hydride at escalated temperature.
Isotopes
As you can see, curium has 96 electrons as well as 96 protons; hence its atomic number is also 96. The electron configuration of an element implies the arrangement of electrons in its orbits.
Electron Configuration of Curium
Find the diagram below and check the shell model of Cm.
[Image will be Uploaded Soon]
Let’s take a quick quiz and check how well do you know about curium!
Quiz
1. What is the Inspiration of “Curium” Name?
Irene-Joliot and Marie Curie
Irene-Joliot and Pierre Curie
Pierre and Marie Curie
Marie Curie
2. Where Does Curium Belong to in the Periodic Table?
Halogens
Alkali metals
Lanthanide series
Actinide series
3. Which of the Following Options Does Curium Suggest?
Non-metal
Metal
Semi-metal
Ceramic
4. Which One is the Half-life of Cm-242 from Below?
Around 163 days
Around 163 seconds
Around 16300 years
Around 163 years
5. Which Curium Isotope Does Find Use in Pacemakers?
Cm – 244
Cm – 252
Cm – 248
Cm – 242
6. Which Device can Transfer Nuclear Energy into Electrical Energy?
Thermocouples
ion accelerator
APXS spectrometers
Salt bridges
7. What is the Neutron Number of Curium?
151
150
152
153
8. Who Identified and Discovered Cm?
Glenn T. Seaborg
Albert Newton
Marie Curie
Pierre Curie
Answer
c. The inspiration of “curium” name was the names of two great physicists -Pierre and Marie Curie.
d. Curium belongs to actinides series.
b. Curium is a metal.
a. The half-life of Cm – 242 is around 163 days.
d. Cm – 242 can be found in pacemakers.
c. APXS spectrometer can convert nuclear energy into electricity.
a. Curium has 151 neutrons.
a. Glenn T. Seaborg identified as well as found out curium.
Uses of Curium
Curium isotopes like Cm–242 and Cm–244 find their usages in the industry of power generation. These two isotopes are used in both thermionic and thermoelectric converters.
For qualitative analysis, curium is also utilised in X-ray spectrometers.
In biotechnology and medical application, Cm is used as a source of power such as pacemakers.
Curium is known as a highly radioactive metal. Due to this property, Cm finds its use in various scientific researches.
These are some crucial curium uses that you should know while learning about this metal.
Effects on Animals and Humans
Curium is considered as a hazardous metal. If inhaled Cm can cause several health disorders.
If ingested, curium can cause gastrointestinal and respiratory depressions. Moreover, it can impact adversely on the liver as well.
Research shows that when Cm isotope is injected in rats, they developed skeletal cancer.
The radioactive emission of Cm can destruct RBC or red blood cells.
If you need any further information about curium, you can simply go through the additional study materials available in our website. Or, for better understanding and doubt clearing, you can also join our online classes where you can meet our chemistry experts.
Use your mobile phone and get our Vedantu app today!
FAQs on Curium
1. What is Curium and what are its key properties?
Curium (symbol Cm) is a transuranic, radioactive chemical element with an atomic number of 96. It is a hard, dense, silvery-white metal belonging to the actinide series. Key properties include its high melting point and intense radioactivity, which causes it to glow a purple-pink colour in the dark. It readily tarnishes when exposed to air.
2. How is metallic Curium typically prepared or synthesised?
Curium does not occur naturally in significant quantities and is produced synthetically. The primary method involves the reduction of its compounds in an environment free of water and oxygen. For example, curium(III) fluoride is reduced using an alkali or alkaline earth metal like lithium or barium in a tantalum crucible. The chemical reaction is: CmF₃ + 3 Li → Cm + 3 LiF.
3. What is the electron configuration of Curium and its chemical significance?
The electron configuration of Curium is [Rn] 5f⁷ 6d¹ 7s². The significance of this arrangement is the half-filled 5f subshell (5f⁷) that results when Curium forms a +3 ion (Cm³⁺) by losing its 6d¹ and 7s² electrons. This half-filled subshell provides extra energetic stability, making the +3 oxidation state the most common and stable for Curium in its compounds.
4. What are the most important applications and uses of Curium?
Despite its rarity and high radioactivity, Curium has several specialised uses. Key applications include:
- Power Generation: Isotopes like Cm-244 are used as a compact power source in radionuclide thermoelectric generators (RTGs) for spacecraft and remote scientific instruments.
- Scientific Analysis: It serves as a source of alpha particles in Alpha Particle X-ray Spectrometers (APXS) used on space probes to analyse the chemical composition of rocks and soil.
- Research: It is used as a starting material to produce heavier transuranic elements and for various scientific research purposes.
5. Why is Curium's +3 oxidation state more stable and common than its other states?
The stability of Curium's +3 oxidation state is a direct consequence of its electron configuration, [Rn] 5f⁷ 6d¹ 7s². To achieve the +3 state, a Curium atom loses its two 7s electrons and one 6d electron. The resulting ion, Cm³⁺, has an electron configuration of [Rn] 5f⁷. This half-filled 5f subshell is an energetically favourable and particularly stable arrangement, similar to how manganese (with a half-filled 3d subshell) exhibits a stable +2 state.
6. Is Curium a naturally occurring element?
No, Curium is considered a synthetic element. It is produced artificially in nuclear reactors by bombarding lighter actinides like plutonium or americium with neutrons. While minute, undetectable traces of Curium might exist in natural uranium ore deposits as a result of a long series of neutron captures and beta decays, it is not found in nature in any practical or significant amount.
7. Why is Curium considered extremely hazardous, and what are its health effects?
Curium is extremely hazardous due to its intense radioactivity. It is a potent alpha particle emitter. If inhaled or ingested, Curium can accumulate in the body, primarily in the bones, liver, and lungs. The persistent alpha radiation emitted at close range damages surrounding cells and tissues, which can disrupt red blood cell production, impair organ function, and significantly increase the long-term risk of developing cancer.
8. How does the chemistry of Curium compare to that of Gadolinium, its lanthanide analogue?
Curium is the actinide analogue of the lanthanide Gadolinium. Both elements share a key chemical similarity: a highly stable +3 oxidation state due to a half-filled f-subshell (Gadolinium has a [Xe] 4f⁷ configuration in its Gd³⁺ ion). This makes their chemistry very similar. However, Curium's valence electrons are in higher energy levels (5f, 6d, 7s) and are less tightly bound than Gadolinium's (4f, 5d, 6s), allowing Curium to exhibit a +4 oxidation state, which is not seen in Gadolinium.
