Isotopes of hydrogen - AbsoluteAstronomy.com

Hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

(H) (Standard atomic mass: 1.00782504(7) u) has three naturally occurring isotope
Isotope
Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons which differs from atom to atom, without changing the designation...

s, sometimes denoted ¹H, ²H, and ³H. Other, highly unstable nuclei (⁴H to ⁷H) have been synthesized in the laboratory but not observed in nature. The most stable radioisotope is tritium, with a half-life of 12.32 years. All heavier isotopes are synthetic and have a half-life less than a zeptosecond (10^-21 second). Of these, ⁵H is the most stable, and the least stable isotope is ⁷H.

Hydrogen

Hydrogen

Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

is the only element

Chemical element

A chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. Familiar examples of elements include carbon, oxygen, aluminum, iron, copper, gold, mercury, and lead.As of November 2011, 118 elements...

that has different names for its isotopes in common use today. The ²H (or H-2) isotope is usually called deuterium

Deuterium

Deuterium, also called heavy hydrogen, is one of two stable isotopes of hydrogen. It has a natural abundance in Earth's oceans of about one atom in of hydrogen . Deuterium accounts for approximately 0.0156% of all naturally occurring hydrogen in Earth's oceans, while the most common isotope ...

, while the ³H (or H-3) isotope is usually called tritium

Tritium

Tritium is a radioactive isotope of hydrogen. The nucleus of tritium contains one proton and two neutrons, whereas the nucleus of protium contains one proton and no neutrons...

. The symbols D and T (instead of ²H and ³H) are sometimes used for deuterium and tritium. The IUPAC states that while this use is common it is not preferred. The ordinary isotope of hydrogen, with no neutrons, is sometimes called "protium". (During the early study of radioactivity, some other heavy radioactive isotopes were given names – but such names are rarely used today).

Hydrogen-1 (protium)

¹H is the most common hydrogen isotope with an abundance of more than 99.98%. Because the nucleus

Atomic nucleus

The nucleus is the very dense region consisting of protons and neutrons at the center of an atom. It was discovered in 1911, as a result of Ernest Rutherford's interpretation of the famous 1909 Rutherford experiment performed by Hans Geiger and Ernest Marsden, under the direction of Rutherford. The...

of this isotope consists of only a single proton

Proton

The proton is a subatomic particle with the symbol or and a positive electric charge of 1 elementary charge. One or more protons are present in the nucleus of each atom, along with neutrons. The number of protons in each atom is its atomic number....

, it is given the descriptive but rarely used formal name protium.

Hydrogen-2 (deuterium)

²H, the other stable hydrogen isotope, is known as deuterium
Deuterium
Deuterium, also called heavy hydrogen, is one of two stable isotopes of hydrogen. It has a natural abundance in Earth's oceans of about one atom in of hydrogen . Deuterium accounts for approximately 0.0156% of all naturally occurring hydrogen in Earth's oceans, while the most common isotope ...

and contains one proton and one neutron

Neutron

The neutron is a subatomic hadron particle which has the symbol or , no net electric charge and a mass slightly larger than that of a proton. With the exception of hydrogen, nuclei of atoms consist of protons and neutrons, which are therefore collectively referred to as nucleons. The number of...

in its nucleus. Deuterium comprises 0.0026 – 0.0184% (by population, not by mass) of hydrogen samples on Earth, with the lower number tending to be found in samples of hydrogen gas and the higher enrichments (0.015% or 150 ppm) typical of ocean water. Deuterium is not radioactive, and does not represent a significant toxicity hazard. Water enriched in molecules that include deuterium instead of normal hydrogen is called heavy water

Heavy water

Heavy water is water highly enriched in the hydrogen isotope deuterium; e.g., heavy water used in CANDU reactors is 99.75% enriched by hydrogen atom-fraction...

. Deuterium and its compounds are used as a non-radioactive label in chemical experiments and in solvents for ¹H-NMR spectroscopy

NMR spectroscopy

Nuclear magnetic resonance spectroscopy, most commonly known as NMR spectroscopy, is a research technique that exploits the magnetic properties of certain atomic nuclei to determine physical and chemical properties of atoms or the molecules in which they are contained...

. Heavy water is used as a neutron moderator

Neutron moderator

In nuclear engineering, a neutron moderator is a medium that reduces the speed of fast neutrons, thereby turning them into thermal neutrons capable of sustaining a nuclear chain reaction involving uranium-235....

and coolant for nuclear reactors. Deuterium is also a potential fuel for commercial nuclear fusion

Nuclear fusion

Nuclear fusion is the process by which two or more atomic nuclei join together, or "fuse", to form a single heavier nucleus. This is usually accompanied by the release or absorption of large quantities of energy...

Hydrogen-3 (tritium)

³H is known as tritium
Tritium
Tritium is a radioactive isotope of hydrogen. The nucleus of tritium contains one proton and two neutrons, whereas the nucleus of protium contains one proton and no neutrons...

and contains one proton and two neutrons in its nucleus. It is radioactive, decaying into helium-3

Helium-3

Helium-3 is a light, non-radioactive isotope of helium with two protons and one neutron. It is rare on Earth, and is sought for use in nuclear fusion research...

through β− decay with a half-life

Half-life

Half-life, abbreviated t½, is the period of time it takes for the amount of a substance undergoing decay to decrease by half. The name was originally used to describe a characteristic of unstable atoms , but it may apply to any quantity which follows a set-rate decay.The original term, dating to...

of 12.32 years. Small amounts of tritium occur naturally because of the interaction of cosmic rays with atmospheric gases. Tritium has also been released during nuclear weapons tests

Nuclear testing

Nuclear weapons tests are experiments carried out to determine the effectiveness, yield and explosive capability of nuclear weapons. Throughout the twentieth century, most nations that have developed nuclear weapons have tested them...

. It is used in thermonuclear fusion weapons, as a tracer in isotope geochemistry

Isotope geochemistry

Isotope geochemistry is an aspect of geology based upon study of the relative and absolute concentrations of the elements and their isotopes in the Earth. Variations in the abundance of these isotopes, typically measured with an isotope ratio mass spectrometer or an accelerator mass spectrometer,...

, and specialized in self-powered lighting

Self-powered lighting

Tritium illumination is the use of gaseous tritium, a radioactive isotope of hydrogen, to create visible light. Tritium emits electrons through beta decay, and when they interact with a phosphor material, fluorescent light is created, a process called radioluminescence...

devices.

The most common method of producing tritium is by bombarding a natural isotope of lithium, lithium-6, with neutrons in a nuclear reactor

Nuclear reactor

A nuclear reactor is a device to initiate and control a sustained nuclear chain reaction. Most commonly they are used for generating electricity and for the propulsion of ships. Usually heat from nuclear fission is passed to a working fluid , which runs through turbines that power either ship's...

.

Tritium was once used routinely in chemical and biological labeling experiments as a radiolabel (this has become less common). D-T nuclear fusion

Nuclear fusion

uses tritium as its main reactant, along with deuterium

Deuterium

, liberating energy through the loss of mass when the two nuclei collide and fuse under massive temperatures.

Hydrogen-4 (quadrium)

⁴H is known as quadrium and contains one proton and three neutrons in its nucleus. It is a highly unstable isotope

Isotope

Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons which differs from atom to atom, without changing the designation...

of hydrogen

Hydrogen

. It has been synthesised in the laboratory by bombarding tritium

Tritium

Tritium is a radioactive isotope of hydrogen. The nucleus of tritium contains one proton and two neutrons, whereas the nucleus of protium contains one proton and no neutrons...

with fast-moving deuterium

Deuterium

nuclei. In this experiment, the tritium nuclei captured neutrons from the fast-moving deuterium nucleus. The presence of the hydrogen-4 was deduced by detecting the emitted protons. Its atomic mass

Atomic mass

The atomic mass is the mass of a specific isotope, most often expressed in unified atomic mass units. The atomic mass is the total mass of protons, neutrons and electrons in a single atom....

is 4.02781 ± 0.00011. It decays through neutron emission

Neutron emission

Neutron emission is a type of radioactive decay of atoms containing excess neutrons, in which a neutron is simply ejected from the nucleus. Two examples of isotopes which emit neutrons are helium-5 and beryllium-13...

with a half-life

Half-life

of (1.39 ± 0.10) × 10⁻²² seconds.

Hydrogen-4.1 (Muonic Helium)

Muonic helium is created by substituting a muon

Muon

The muon |mu]] used to represent it) is an elementary particle similar to the electron, with a unitary negative electric charge and a spin of ½. Together with the electron, the tau, and the three neutrinos, it is classified as a lepton...

for one of the electrons in Helium-4. The muon orbits much closer to the nucleus than the electron. Muonic helium can therefore be regarded as an isotope of hydrogen whose nucleus consists of two neutrons, two protons and a muon, with a single electron orbiting the nucleus. A muon weighs about 0.1u, hence the name hydrogen-4.1. Hydrogen 4.1 can bond with other atoms, and behaves more like a hydrogen atom than like an inert helium atom.

Hydrogen-5

⁵H is a highly unstable isotope

Isotope

of hydrogen

Hydrogen

. The nucleus consists of a proton and four neutrons. It has been synthesised in the laboratory by bombarding tritium

Tritium

Tritium is a radioactive isotope of hydrogen. The nucleus of tritium contains one proton and two neutrons, whereas the nucleus of protium contains one proton and no neutrons...

with fast-moving tritium nuclei. In this experiment, one tritium nucleus captures two neutrons from the other, becoming a nucleus with one proton and four neutrons. The remaining proton may be detected, and the existence of hydrogen-5 deduced. It decays through double neutron emission

Neutron emission

and has a half-life

Half-life

of at least 9.1 × 10⁻²² seconds.

Hydrogen-6

⁶H decays through triple neutron emission

Neutron emission

and has a half-life

Half-life

of 2.90×10⁻²² seconds. It consists of 1 proton and 5 neutrons.

Hydrogen-7

⁷H consists of a proton

Proton

and six neutron

Neutron

s. It was first synthesised in 2003 by a group of Russian, Japanese and French scientists at RIKEN

RIKEN

is a large natural sciences research institute in Japan. Founded in 1917, it now has approximately 3000 scientists on seven campuses across Japan, the main one in Wako, just outside Tokyo...

's RI Beam Science Laboratory by bombarding hydrogen

Hydrogen

with helium-8 atoms. In the resulting reaction, the helium-8's neutrons were donated to the hydrogen's nucleus. The two remaining protons were detected by the "RIKEN telescope", a device composed of several layers of sensors, positioned behind the target of the RI Beam cyclotron.

Table

nuclide symbol	Z(p Proton The proton is a subatomic particle with the symbol or and a positive electric charge of 1 elementary charge. One or more protons are present in the nucleus of each atom, along with neutrons. The number of protons in each atom is its atomic number.... )	N(n Neutron The neutron is a subatomic hadron particle which has the symbol or , no net electric charge and a mass slightly larger than that of a proton. With the exception of hydrogen, nuclei of atoms consist of protons and neutrons, which are therefore collectively referred to as nucleons. The number of... )	isotopic mass (u)	half-life	decay mode(s)	nuclear spin	representative isotopic composition (mole fraction)Refers to that in water.	range of natural variation (mole fraction)
	1	0		StableGreater than . See proton decay Proton decay In particle physics, proton decay is a hypothetical form of radioactive decay in which the proton decays into lighter subatomic particles, such as a neutral pion and a positron... .This and ³He are the only stable nuclides with more protons than neturons		⁺		–
²H Deuterium Deuterium, also called heavy hydrogen, is one of two stable isotopes of hydrogen. It has a natural abundance in Earth's oceans of about one atom in of hydrogen . Deuterium accounts for approximately 0.0156% of all naturally occurring hydrogen in Earth's oceans, while the most common isotope ... Produced during Big Bang nucleosynthesis Big Bang nucleosynthesis In physical cosmology, Big Bang nucleosynthesis refers to the production of nuclei other than those of H-1 during the early phases of the universe...	1	1		Stable		1⁺	Tank hydrogen has a abundance as low as (mole fraction).	–
³H Tritium Tritium is a radioactive isotope of hydrogen. The nucleus of tritium contains one proton and two neutrons, whereas the nucleus of protium contains one proton and no neutrons... Produced during Big Bang nucleosynthesis, but not primordial, as all such atoms have decayed to ³He	1	2			β^- Beta decay In nuclear physics, beta decay is a type of radioactive decay in which a beta particle is emitted from an atom. There are two types of beta decay: beta minus and beta plus. In the case of beta decay that produces an electron emission, it is referred to as beta minus , while in the case of a...	⁺	TraceCosmogenic Cosmogenic nuclide See also Environmental radioactivity#NaturalCosmogenic nuclides are rare isotopes created when a high-energy cosmic ray interacts with the nucleus of an in situ solar system atom, causing cosmic ray spallation...
	1	3		[]	n Neutron emission Neutron emission is a type of radioactive decay of atoms containing excess neutrons, in which a neutron is simply ejected from the nucleus. Two examples of isotopes which emit neutrons are helium-5 and beryllium-13...	2⁻
	1	4		> ?	n	(⁺)
	1	5		[]	3n	2⁻#
	1	5		[]	4n	2⁻#
	1	6	#	# []#		1/2⁺#

In fiction

In the 1955 satirical novel The Mouse That Roared
The Mouse That Roared
The Mouse That Roared is a 1955 Cold War satirical novel by Irish-American writer Leonard Wibberley, which launched a series of satirical books about an imaginary country in Europe called the Duchy of Grand Fenwick...

, the name quadium was given to the hydrogen-4 isotope that powered the Q-bomb that the Duchy of Grand Fenwick captured from the United States.

External links

News of hydrogen-7 discovery
Article on hydrogen-4 and hydrogen-5 (login required)

|- style="text-align:center"
| width="30%" | No lighter element
| width="40%" | Isotopes of hydrogen
| width="30%" | Isotopes of helium
Isotopes of helium
Although there are eight known isotopes of helium , only helium-3 and helium-4 are stable. All radioisotopes are short-lived, the longest-lived being 6He with a half-life of 806.7 milliseconds. The least stable is the diproton, with a half-life of 3x10-27 seconds, even shorter than that of 5He...

|- style="text-align:center"
| colspan="3" | Index to isotope pagesTable of nuclides

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.