Californium can be described as a radioactive chemical element having the symbol Cf with an atomic number 98. This element was first synthesized in 1950 at the National Laboratory of Lawrence Berkeley (after that, the University of California Radiation Laboratory) by bombarding the curium with alpha particles (with helium-4 ions).
This is an actinide element, which is the sixth transuranium element to be synthesized, and it also has the second-highest atomic mass of all the elements, which are being produced in huge amounts to notice with the unaided eye (after that of einsteinium). Also, this element was named after the state of California University.
Californium is the element that is available in two forms under normal pressure and the third form at high pressure.
When exposed to air, it tarnishes gradually and is attacked by steam and acids readily. The only stable ion is the Californium (III) in aqueous solutions, which cannot be reduced or oxidized.
There are various compounds of californium that exhibit various kinds of properties. For instance, Californium - 252, which is a very strong emitter of neutrons.
It is the heaviest actinide, showing covalent properties same as californium borate.
Naturally, the element is not available on Earth. It is found in the vicinity of nuclear facilities and in research laboratories because it is used in mineral prospecting and medical diagnosis.
Let us discuss the chemical properties of californium as listed below:
It belongs to the group of Actinides.
It has a period value of 7.
The atomic number of californium is 98.
Its state at 20°C is Solid.
The electron configuration can be given as [Rn]5f10 7s2.
The ChemSpider id can be given as 22433 (ChemSpider is the free database of chemical structure).
It holds a melting point of 1652°F, 900°C, 1173 K.
It has an unknown boiling point.
Its density is 15.1 g cm−3.
Its relative mass is .
Its key isotopes are 249Cf, 252Cf.
It contains the CAS number 7440-71-3.
The californium traces can be found near facilities that use medical treatments and mineral prospecting. This element is fairly insoluble in water, whereas it adheres well to the ordinary soil. Its concentrations in the soil can remain 500 times higher than the water that surrounds the soil particles.
Fallout formed from the atmospheric nuclear testing before 1980 contributed a less amount of californium to the environment. The californium isotopes of mass numbers, 252, 249, 253, 254 can be observed in the radioactive dust, which is collected after a nuclear explosion from the air. Also, it is not a major radionuclide at the sites of the United States Department of Energy legacy because it was not produced in large quantities.
Once, the californium was tested to be made in supernovas because their decay matches the 60-day half-life of 254Cf element. However, the subsequent studies have failed in demonstrating any californium spectra, and now, the supernova light curves are thought to follow the nickel-56 decay.
The transuranic elements that fall from americium to fermium, with californium, which occurred in a natural nuclear fission reactor naturally at Oklo, but it no longer performs so.
Californium, that bioaccumulates in skeletal tissue, releases radiation that disrupts the ability of the body forming red blood cells. This element plays no natural biological role in any organism because of its low concentration and intense radioactivity in the environment.
Californium can enter into the body from taking drinks or contaminated food or breathing air consisting of the element's suspended particles. Only 0.05 percent of the californium will reach the bloodstream at one single instance. Whereas about 25 percent of the californium will be deposited in the liver, 65 percent in the skeleton, and the remaining in other organs, or excreted, majorly in the urine.
Half of the californium that is deposited in the liver and skeleton are gone in 20 and 50 years, respectively. Californium that is in the skeleton adheres to bone surfaces before it slowly migrate throughout the bone.
This element is most dangerous for the body if consumption happens. Also, californium-251 and californium-249 can cause external tissue damage through gamma-ray emission. Ionizing radiation, which is emitted by the californium on bone and liver, can cause cancer.
Some of the californium uses can be listed as follows:
Californium is a very good neutron source, and this makes it a useful property in a nuclear power plant as a source of neutron startup.
Also, it is useful to detect the trace elements in samples with the analysis of neutron activation.
Some detections such as neutron radiography, portable metal detectors, and fuel rods will use the neutron penetration property of californium.
It is also employed to treat many cervical and brain cancers.
1. Give Some Applications of Californium?
Ans: Californium-252 has various specialized applications as a strong neutron emitter, and every microgram of fresh californium makes 139 million neutrons per minute. This property makes the californium useful as a neutron startup source for some nuclear reactors and as a portable (a non-reactor based) source of neutron for the analysis of neutron activation to detect the elements' trace amounts in samples.
The californium neutrons are employed as particular cervical and brain cancer treatment, where the other radiation therapy is ineffective. It is also used with bulk material analyzers in cement & coal industries and the online elemental coal analyzers.
2. What are the Forms of Californium?
Ans: There are two crystalline forms for californium under normal pressure: one above and the other below 900 °C (1,650 °F). At the same time, there is a third form that exists at high pressure. At room temperature, it slowly tarnishes in the air. A +3 oxidation state dominates the californium compounds.
The most stable twenty known isotopes of californium are californium-251, with a half-life of 898 years. This short half-life is the element not found in significant quantities in the crust of Earth. Californium-252 has a half-life of about 2.645 years, which is the most common isotope used and produced at Oak Ridge National Laboratory, United States, and Research Institute of Atomic Reactors, Russia.