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Francium (87 Fr) has no stable isotopes, thus a standard atomic weight cannot be given. Its most stable isotope is 223 Fr with a half-life of 22 minutes, occurring in trace quantities in nature as an intermediate decay product of 235 U.
A sample of thorium. The thorium fuel cycle is a nuclear fuel cycle that uses an isotope of thorium, 232 Th, as the fertile material. In the reactor, 232 Th is transmuted into the fissile artificial uranium isotope 233 U which is the nuclear fuel. Unlike natural uranium, natural thorium contains only trace amounts of fissile material (such as ...
Chemical substance – Form of matter; Inorganic compounds by element; List of alloys; List of alkanes; List of elements by name; List of minerals – List of minerals with Wikipedia articles; List of alchemical substances; Polyatomic ion – Ion containing two or more atoms; Exotic molecules – Atoms composed of exotic particles can form ...
231 Th has 141 neutrons. It is the decay product of uranium-235. It is found in very small amounts on the earth and has a half-life of 25.5 hours. [53] When it decays, it emits a beta ray and forms protactinium-231. It has a decay energy of 0.39 MeV. It has a mass of 231.0363043 u.
Chemical formula Synonyms CAS number CAgO carbonylsilver: CCl 2 F 2: dichlorodifluoromethane freon-12: 75-71-8 CCl 4: carbon tetrachloride tetrachloromethane: 56-23-5 C(CN) 4: tetracyanomethane: 24331-09-7 CFCl 3: trichlorofluoromethane freon-11: 75-69-4 CFCl 2 CF 2 Cl: chlorotrifluoromethane freon-13: 75-72-9 CHCl 3: chloroform ...
In chemistry, the mass fraction of a substance within a mixture is the ratio (alternatively denoted ) of the mass of that substance to the total mass of the mixture. [1] Expressed as a formula, the mass fraction is:
The names "caffeine" and "3,7-dihydro-1,3,7-trimethyl-1H-purine-2,6-dione" both signify the same chemical compound.The systematic name encodes the structure and composition of the caffeine molecule in some detail, and provides an unambiguous reference to this compound, whereas the name "caffeine" simply names it.
Theoretical chemistry requires quantities from core physics, such as time, volume, temperature, and pressure.But the highly quantitative nature of physical chemistry, in a more specialized way than core physics, uses molar amounts of substance rather than simply counting numbers; this leads to the specialized definitions in this article.