TRANSFERMIUM ELEMENTS
-------------------
John Pazmino
NYSkies Astronomy Inc
www.nyskies.org
nyskies@nyskies.org
2011 June 10
Introduction
----------
On 2011 June 1 the International Union of Pure and Applied
Chemistry (IUPAC) confirmed the discovery of new elements number 114
and 116. They were created a few years earlier by a joint team from
Dubna lab in Russia and Livermore lab in the United States.
It is several years since the last ammouncement of new elements,
moving readers to ask about the process of finding and naming them.
Some recall element discoveries from the 18th and 19th centuries and
about new elements from the atom bomb program.
New elements
----------
In the past, thru the mid 20th century, elements were 'found' or
'discovered' in the traditional scientific sense of lurking in nature
waiting for humans to pick them out. A scientist suspects the element
is in a certain mineral and extracts it by chemical or physical means.
This is no longer the situation. Elements uncovred in the past
seventy years were made in atomic laboratories in various countries.
Because all of the newer elements are higher, farther, in the periodic
table of elements than uranium, element #92, they as a group are
called transurnaium elements.
They have more protons than uranium, have higher atmoic number.
They are almost all artificially created, not found in nature. We now
know of elements numbers 93 thru 116 with gaps at 113 and 115.
The method of making transuranium element was part of the wrok to
build the atom bomb in the 1940s. Uranium atoms were beamed with
neutrons. The atom absorbed the neutrons. The atom, now unstable,
undergoed decay by ejecting electrons, which converted some of the
neutrons into protons. Since an element is defined by the number of
protons in the atom, the addition, by this conversion, of protons made
a new element. Elements 93, neptunium, thru 100, fermium, were
produced in this way.
Transfermium elements
-------------------
By the nature of atoms, fermium is the highest element that can be
made by neutron absorption. Attempts to pack more neutrons into an
atom, inteding to make elements 101 and higher, fail. The engorged
atom decays by spitting out alpha particles, helium nuclei, to lower
the number of protons and fall into already known elements.
Since the formation of fermium, all heavier elements are created
by beaming a target with an other atom. The beam and target atoms fuse
together to form the atom with a higher number of protons. In the
process some excess neutrons may be ejected.
Note well the paradigmatic shift in method between elements 93
thru 100 and those 101 and higher. Elements from 101 and heavier are
called transfermium elements. There seems at present to be no limit to
the ultimate heaviest atom that can be created by the fusion method.
Nucleons
------
Each element has an atomic or element number. This is the count of
protons in its nucleus, which actually defines the atom to be the
given element and no other. Because the element has its unique atomic
number often this number is commonly omitted from discussion. Saying
'oxygen' means 'element #8' and 'eight protons'.
If the atom has 7, not 8, protons it can not be oxygen. It is
nitrogen. If it has 9 protons, it is fluorine.
In addition to protons the atom has neutrons. The neutrons are not
fixed in count for a given element. An atom of a given element may
have a range of neutrons. Protons and neutrons are about the same
mass, one atomic unit, and are collectively called necleons.
The count of nucleons is the mass number of the atom. Oxygen-15
has 8 protons (to be oxygen) and 7 neutrons, for a total of 15. The
atom has mass of 15 units and has mass numgber 15. Note that the
proton count was omitted. It is implied by the element name 'oxygen'.
The atomic or element number is symboled as Z; mass number, A. We
say oxygen-15 has Z = 8 and A = 15. The count of neutrons, N, is
commonly missed out. It is found by subtracting the ztomic number Z
from the mass number A: N = (A - Z).
The proton has one unit of positive electric charge, +1. The
neutron has no charge. In free range atoms, electrons orbiting the
nucleus balance the positive proton charge by their own negative
charge. The elecrons has one unit of negative charge, -1.
In just about all atomic work the atom is stipped of its
electrons, leaving a bare nucleus with a postive charge equal to the
count of protons. The nnucleus can then be manipulated by magnetic
fields in an atom smasher.
Isotopes
------
Altho an element must have its proper number of protons, it may
have a varying number of neutrons. Each distinct count of neutrons in
the nucleus of the element is an isotope of that element. Oxygen with
8 protons may have from 5 thru 10 neutrons. Oxygen has six isotopes:
oxygen-8, oxygen-9, oxygen-10,... . The most common isotope in nature
has 8 neutrons.
Some isotopes are rare or can be made only artificially. Others
occur in nature. The ratio of isotopes in a given sample of the
element varies with the origin and history of that sample. Certain
isotopes may be thermally or chemicly depleted, disntegrated by
radioactivity, or were never present in the sample.
The mix of isotopes in a sample yields the atomic mass. It is NOT
the mass number. Suppose an element has two isotopes in a sample, 25%
of mass number 25 and 75% of mass number 28. The mix of the two is
atomic mass = (0.25) * (25) + (0.75) * (28)
= (6.25) + (21.0)
= (27.25)
This sample has atomic mass 27.25. This is the value used in
chemistry being that the element is taken from the natural mixture and
not seaprated apart.
An elemnet may have 'missing' isotopes, a gap in the range of mass
numbers. The missing isotopes may be not yet found or made or they may
be precluded by nuclear theory.
A related term is 'nuclide' meaning a nucleus of a unique mass and
atomic number. Some scientists say an isotope applies only to nuclei
of an element with two or more distinct nuclides, of the same atmoic
number but different mass number. By simlar technicaiity an atom means
the nucleus with its electrons, not the nucleus alone.
In litterature ranging from casual to technical the terms stom,
isotope, nucleus, nuclide are commoly interchangeabe. As long as the
context is clear, there should be no serious confusion.
Radioactivity
-----------
An isotope may be stable, not spontaneously decaying into other
isotopes. Every element found in nature has at least one stable
isotope, else on the geologic timescale it would be all decayed away.
In some cases it is replenished as a product of an other element's
decay within the same sample.
Isotopes that decay on their own, without external stimulus, are
radioactive. These are also found in nature. For the most part humans
and other life evolved to tolerate them. In concentration, like in a
laboratory, all radioactive isotopes are a threat to life because the
energies of their decay emissions are greater than that needed to
dissociate molecules in organic material in the human body.
Alpha, beta, gamma
----------------
When radioactivity was discovered in the 1890s, three emissions
from a decaying atom were recognized. They were named alpha, beta, and
gamma rays. At that time the notion of particulate and undulate
radiation was not yet known.
An alpha 'ray' is the nucleus of a helium atom, made of 2 protons
and 2 nuetrons. It has atomic or element number 2, mass number 4. An
alpha particle has electric charge +2, that of its two protons. An
alpha particle is symboled by alpha or He-4.
A beta 'ray' is an electron. Its mass is about 1/1,500 of a proton
or neutron and has a -1 electric charge. A beta particle when taken in
or released by an atom leaves the mass number unchanged but it can
alter the number of protons. A beta particle is symboled beta or e-.
A gamma ray is a quantum of electromagnetic energy. It has neither
mass nor charge and is cited by its energy, wavelength, or frequency.
Its emission from a nucleus does not change the atomic or mass number.
The energy of the gamma radiation can help verify the creaton of
elements. A gamma ray has symbol gamma.
Alpha decay
---------
An alpha decay is the release of an alpha particle from a nucleus.
The remaining nucleus has two fewer protons and two fewer neutrons. It
has mass number less by 4 units and atomic number less by 2 units.
For the fictitious element pazminium an alpha decay is
|200| |198| | 2|
|Pz | --> |On | + |He |
|500| |496| | 4|
The upper number is the atomic or element number; middle, element
symbol; lower, mass number. Pazminium turns into elemnet onimzapium by
releasing an alpha particle. It is two atomic numbers lower than
pazminium and has four units less of mass number.
Beta decay
--------
A beta decay is the release of a beta particle from a nucleus.
The remaining nucleus has the same mass number but increases its
atomic number by 1.
The end result is that one of the neutrons converts into a proton
and electron. The proton stays in the nucleus. The electron is
expelled.
For pazminium a beta decay is
|200| |201| | 0|
|Pz | --> |Mp | + |e- |
|500| |500| | 0|
Pazminium decays into element minopazium which has one more proton
and one less neutron than pazminium. The exchange leaves the mass
number unaltered.
Electron capture
--------------
Also called beta capture where the nucleus grabs a free electron
in its vicinity. The end effect is that the electron combines with a
proton in the nucleus to become a neutron. The nucleus has the same
mass number but one unit less of atomic number.
Electron or beta capture is sometimes symboled by epsilon.
A beta capture by pazminium is
|200| | 0| |199|
|Pz | + |e- | --> |Nz |
|500| | 0| |500|
Pazminium by acquiring the electron turns into nopazmium with the
same mass number but one fewer protons.
Spontaneous fission
-----------------
Certain nuclei disintegrate on their own by splitting into two
smaller nuclei. In a spontaneous fission neutrons may also be split
off because the particular derivative isotopes don't need them.
A example of spontaneous fission eith pazminium is
|200| |130| | 70| | 0|
|Pz | --> |By | + |Yb | + 7 |n |
|500| |320| |173| | 1|
Pazminium falls apart into brooklynium and ytterbium (a real
element). Both isotopes together need only 293 neutrons. The seven
extra from the original 300 (= 500 nucleons - 200 protons) are
discarded.
All four modes of decay are observed in nuclear experiments. Most
are within theory to predict and look for. Others are unexpected. In
addition to the occurrence of the particular deecay, the lab must
measure the energy of the emitted particles and the delay before they
are expelled. These help identify the parent nucleus, specially if
it's the newly created one.
Halflife
------
In a sample of radioactive atoms, each will disintegrate into
byproducts after an indeterminate random amount of time. The instant
of decay for a specific atom is impossible to predict, but statisticly
it happens after a certain delay after the atom is created.
The continuing decay of the sample of atoms, each atom after its
own unique delay, gradually decreases the count of original atoms and
replaces it with decay pruducts. For a substantial number of atoms the
distribution of the individual delays before disintegration produces a
time sequence of declining number of original atoms.
It is an exponential decline such that at equal intervals of time
after a given moment there is consumed a particular fraction of these
atoms. Of special interest is the interval for consming one-half of
the original atoms. This interval is the atom's halflife.
The original count, number, amount is that at the start of each
halflife interval. Since a sample is examined after some time of
existence of the atoms, one half of the amount at that moment is
consumed, converted to other atoms, in the next halflife interval.
For bulk amounts of atoms there are enough atoms to build a smooth
statistical curve of decay, amount vs time, and determine the
halflife. When, as in the usual case for the new elements, there are
only a few aroms to start with, the statistics for these atoms are way
too coarse and gtainy for a good halflife determination.
In the extreme case of having only two atoms to start with, which
can happen in element synthesi sexperiments, the halflife is
meaningless. After some time delay the first atom decays. One half of
the sample is left so the halflife seems to be the measured delay of
the first atom.
Because there is only one atom left, there can not be an event
that leaves a second one-half of the sample. Once that atom delays,
the sample is all gone. This is why for many of the new nuclei the
halflife is not cited.
When the experiment is repeated, the two atoms will decay at times
other than those for the earlier experiment. Such behavior of atoms
makes the new element all the harder to confirm.
Decay chain
---------
The resulting atoms of one decay can themselfs decay into other
atoms. They are not necessarily stable or very long-lasting isotopes
that end the decay process. The decay can continue level after level
until such stable or enduring isotopes are reached. The sequence of
decays from the original highest element to the final product is the
decay, or reaction, chain for that element.
Here I follow the reaction chain thru fermium, einsteinium, or
californium becuae lower than this level the atoms are familiar ones
with well-known properties.
The word 'chain' here is distinct from its use in a nuclear bomb.
Here it refers to the cascade decay of a parent element into a series
of derivatives. Only a small number of parents are needed to give a
good decay chain to document the events.
The 'chain reaction' for nuclear bombs is a repetition of the SAME
decay process among the SAME parent atoms in a bulk sample of the
/element. This happens rarely in nature but can be induced by bringing
into one place enough of the element. The decay products, neutrons in
a simple atom bomb, hit other atoms, forcing then to decay.
The amount of bulk atoms to start a chain rection is its critical
mass. A lesser mass will not sustain the chain reacton because there
are too few other atoms to intercept the emitted neutrons. The
neutrons pass out of the bulk and are lost.
Multiple decays
-------------
An isotope may have several methods of decay. The probability of
each is a statistical function based on a bulk sample of the isotope.
Which decay a given atom does is a random and unpredictable event. The
byproducts of the bulk sample are a mix of those from each decay
method in the ratio of their probabilities.
In this article I use only the moost probably method, else the
decay chain will grow too many branches. In nuclear studies such
ramified decay chains are the normal situation. It is a task of skill
and craft to sort out the decay products and determine their parent
atoms.
Beaming a target
--------------
Transfermium elements are made by beaming a target atom with
accelerated particles from an atom smasher. The machine is typicly an
existing particle accelerator operated at a much lower energy than for
smahing atoms or subatomic particles. I don't recall an atom smasher
made purposely for the synthesis of new chemical elements.
For element synthesis the beam is composed of a particular atom.
Elements lower in atomic number than 101 mendelevium were beamed with
neutrons.
The target is a tool made of many parts and chemical elements,
mostly metals. The atoms to be beamed upon are embedded in or on a
plate or slab mounted in the target tool.
The collision between beam and target smash off fragments, ehich
are collected and examined for presence of the new element. Only
single atoms of the new element are created. Most of the fragments are
form other elements of little value for the instant experiment. In
addition, several isotopes of the new element may be formed, each with
its own properties and behavior.
The lab must sort out the debris and, hopefully, extract the new
atoms and record them for claim of discovery. In some cases there are
enough factors of error and uncertainty that the report unravels under
closer peer review. The claim is set aside.
Fusion
----
The beaming must be of low enough energy to preent fission of the
target nuclei, which ruins the experiment. The beam atoms must 'stick'
to the target atoms and fuse together. At worse only neutrons are
ejected from the newly fused atom.
The beam and target atoms are chosen such that the sum of their
atomic numbers equals that of the desired new atom. The sum of mass
numbers must be in the range expected for isotopes of the new atom,
Labs use either cold or hot fusion. Cold fusion is done with a
beam energy, the energy of each particle in the beam, of up to a few
tens of megaelectron-volts. This beaming tends to get all the
ingredient neutrons to assemble into the new atom. Only a couple are
expelled and lost.
Hot fusion is for beams of higher energy that, among other
effects, causes many of the ingredient neutrons to be ejected. There
are technical reasons to choose one or other, which I skip here,
Several methods or several isotopes of beam and target were tried
to make each of the transfermium elements. I illustrate only one for
each elements as an example. In the sections for each element I give
only a brief history. Each element has a dense history in the physics
and chemistry litterature.
Naming the element
----------------
The credited lab earns the right to suggest the name and symbol
for the element in accordance to rules of nomenclature. After review
and comment International Union of Pure and Applied Chemistry (IUPAC)
announces the official name and symbol, which is not neccesariky the
suggested one.
Unlike in former years, the dsicovery lab does not assert the
name, but only offers a suggested one. IUPAC may, and did on occasion,
turn it down in favor of some other name.//
The name can be almost anythig, as long as it's not offensive or
overly long and clumsy to pronounce. Usual themes are a geographic
place, chemical or physical property, mythical person or place,
celestial body, and scientists. As far as practical the base of the
name is promounced with its own original sounding.
The ending '-ium' or '-um' is appeded to the base name to make it
a second declension neuter noun, like the classical metrtals and most
other elemnets. It is promounced '-ee-yumm' or '-yumm'. The accent of
the full name almost naturally falls on the syllable before the 'ium'
or 'um' ending.
If the suggested name is rejected, it is removed from future
assignment for an other element. This prevents the confusion that
started in the Transferium War when the same name was applied to
different elements.
Systematic nomenclature
---------------------
In 1979 IUPAC proposed a provisional naming system for new
elements. This is the 'systematic nomenclature' and it applies only to
the then unnamed elemnets. It was substantailly ignored by labs
striving to create and then name new elements. The procedure was
officiated in 1990, after some elemnets were already formed and named.
The system is not retroactively used for previously named
elements, not even to discuss them in the period before they were
formally named. Yet the scheme starts with element number 101, which
was already named. Once IUPAC officially names an element the
systematic name passes into history.
The systematic names are made from the atomic numbers. Each digit
becomes a syllable based on Latin and Greek words for the digit.
The words are chosen to avoid conflict of initial letter by which
the element symbol is composed. The syllables are concatenated in the
order of the digits and terminated by 'um' or 'ium'.
The symbol of the new element is the initials of the three
syllables, the first capitalized. Having three chars in the symbol
distinhuishws the new nuclei from the named ones because the symbols
for all named nuclei have one or two chars.
-------------------------
# | name | lang | source
--+------+-------+--------
0 | nil | Latin | nihil = nothing
1 | un | Latin | unus = one
2 | bi | Latin | bis = twice (adverb)
3 | tri | Latin | tres = three
4 | quad | Latin | quattuor = four
5 | pent | Greek | pente = five
6 | hex | Greek | hex = six
7 | sept | Latin | septem = seven
8 | oct | Latin | octo = eight
9 | enn | Greek | ennea = nine
-------------------------------
Example: 116 = 1, 1, 6 = un, un, hex, ium = ununhexium, with symbol
Uuh. Element 130 is untrinilium with symbol Utn. These names can be
clunky. Ununhexium is 'oon-oon-HEKS-ee-yumm' and untrinilium is 'oon-
trih-NIH-lee-yumm'. Many scientists refer to the unnamed elements as
'element such-&-scuh'.
These names say nothing about the claimed or proved existence of
the elements. They are merely employed in any dialog about the
elements until a proper name is approved.
Transfermium War
--------------
Since World War II, as a spinoff of the atom bomb effort, the
method of 'finding' elements is no longer chemical but synthetic. As
the nuclear labs artificially made a new nucleus, they applied names
to them. Conflicts developed.
United States and Soviet Union were in a Cold War competition to
discover new elements and then claim namming rights for them. This is
a fascinating facet of Soviet-American relations of the era, richly
detailed in many articles and books.
Resolution was proposed by IUPAC in 1994 (IUPAC 94 in the table
below) that was not accepted by the contending parties. After more
discussion the final official names wre agreed on from IUPAC's report
of 1997 (IUPAC 97).
----------------------------------------------------
name element 101 element 102 element 103
--- ------ ------------- ---- ------- -------------
systematic unnilunium unnilbium unniltrium
American mendelevium nobelium* lawrencium
Russian --- --- ---
German --- --- ---
IUPAC 94 mendelevium nobelium lawrencium
IUPAC 97 mendelevium nobelium lawrencium
===================================================
name element 104 element 105 element 106
--- ------ ------------- ---- ------- -------------
systematic unnilquadium unnilpentium unnilhexium
American rutherfordium hahnium seaborgium
Russian kurchatovium nielsbohrium ---
German --- --- ---
IUPAC 94 dubnium joliotium rutherfordium
IUPAC 97 rutherfordium dubnium seaborgium
===================================================
name element 107 element 108 element 109
--- ------ ------------- ---- ------- -------------
systematic unnilseptium unniloctium unnilennium
American --- --- ---
Russian --- --- ---
German nielsbohrium hassium meitnerium
IUPAC 94 bohrium hahnium meitnerium
IUPAC 97 bohrium hassium meitnerium
---------------------------------------------------
* proposed by Sweden for a mistaken discovery of element 102, then
proposed again by US after a positive formation of the elment.
For elements 101, 102, 103 IUPAC accepted the prevailing names
already in wide circulation. There was little objection to these
names, causing no reason for IUPAC to offer alterantives.
After this era there was no more Soviet Union. The newly formed
Russia began collegial cooperation in nuclear sciences. All later
elements were named without controversay.
To give a 'national' name for the German work, element 110 is
named darmstadtium for the town of the German lab. Japan also works on
nuclear synthesis but as yet did not confirm any new element. When it
does, a national name may be officiated for it.
Synthesis details
---------------
Below I give for each transfermium element a summary of its
creation and a decay chain. The reaction chain is that from the
confirmed work and is only one of usually many that tried various
combinations of target and beam isotopes.
Each nucleus is a box:
|ZZZ| <-- elemnet number
|El | <-- element symbol
|AAA| <-- mass number
The decay chain is carried down to familiar elements at or just
below fermium. A continuation mark is attached to the last atom in the
depicted chain:
|ZZZ| )
|El | )-- last nucleus shown in diagram
|AAA| )
----- <-- element continues the decay chain
|...| <-- element continues to steps not shown
When a chain ends by spontaneous fission, I note this by ' -->
fission' without showing the split off atoms.
Each element is titled with atomic number, sumbol, name.
100 - Fm - fermium
---------------
Fermium was first found in radioactive debris from the Ivy Mike
atom bomb test in 1952. It was formed from neutron absorption in
uranium and several decay nuclei were confirmed as coming from it.
This work was a military secret until 1954, when public disclosure
was allowed. UC-Berkeley labs made fermium artificially by beaming
neutrons at plutonium.
Confirmation was informal at that time but it was generally
accepted in 1954 that UC-Berkeley was the first to find and then
create fermium. UC-Berkeley suggested the name in 1954 and IUPAC
approved it also in 1954 with no objections.
The original reaction in the bomb test was
| 92| | 0| | 92| | 99| | 0|
|U | + 17 |n | --> |U | --> |Es | + 7 |e- |
|238| | 1| |255| |255| | 0|
-----
| 99| |100| | 0|
|Es | --> |Fm | + |e- |
|255| |255| | 0|
-----
| 2| | 98| |100|
|He | + |Cf | <-- |Fm |
| 4| |251| |255|
101 - Md - mendelevium
--------------------
The UC-Berkeley lab first produced mendelevium in 1955 by beaming
an einsteinium target with alphas.
| 99| | 2| |101| | 0|
|Es | + |He | --> |Md | + |n |
|253| | 4| |256| | 1|
-----
|101| | 0| |100|
|Md | + |e- | --> |Fm |
|256| | 0| |256|
-----
|100|
|Fm | --> fission
|256|
UC-Berkeley in 1955 suggested the name mendelevium with symbol Mv.
IUPAC in 1958 and again in 1993 confirmed the 1955 discovery. It then
also approved the name but replaced the suggested symbol Mv with Md.
Mendelevium is the first element produced in only single atom
quantity, 17 in all by the initial production. Previous elements were
made in subtantial amounts of millions to billions of atoms. All later
ones were made in single atom amounts.
102 - No - nobelium
-----------------
The Nobel Institute, Sweden in 1957 first reported nobelium
creation and proposed name nobelium, symbol No. This work could not be
replicated by other labs. In 1966 the USSR lab in Dubna successfully
created noelium, for which it proposed the name joliotium, symbol Jo.
IUPAC in 1993 confirmed the 1966 Dubna work. In 1997 it assigned
the originally suggested name nobelium, No.
The Dubna reaction is:
| 92| | 10| |102| | 0|
|U | + |Ne | --> |No | + 4 |n |
|238| | 22| |256| | 1}
-----
|102| |100| | 2|
|No | --> |Fm | + |He |
|256| |252| | 4|
-----
|100| | 98| | 4|
|Fm | --> |Cf | + |He |
|252| |248| | 4|
-----
|...|
103 - Lr - lawrencium
---------------
UC-Berkeley in 1961 first produced lawrencium by beaming
californium with boron. It suggested the name and symbol Lw. The lab
changed the symbol to Lr in 1963.
In 1967 the Dubna lab in USSR formed lawrencium by beaming
americium with oxygen.
In 1993 IUPAC credited both labs with the discovery. IUPAC
ratified name lawrencium and Lr in 1997.
The Berkeley group used several combinatons of californium-boron
isotopes, each with its own reactin chain. One example is:
| 98| | 5| |103| | 0|
|Cf | + |B | --> |Lr | + 5 |n |
|252| | 11| |258| | 1|
-----
|103| |101| | 2|
|Lr | --> |Md | + |He |
|258| |254| | 4|
-----
|101| | 0| |100|
|Md | + |e- | + |Fm |
|254| | 0| |254|
-----
| 4| | 98| |100|
|He | + |Cf | <-- |Fm |
| 2| |250| |254|
-----
|...|
The Dubna lab tried several isotopes of americium-oxygen. One
chain is:
| 95| | 8| |103| | 0|
|Am | + |O | --> |Lr | + 5 |n |
|243| | 18| |256| | 1|
-----
|103| |101| | 2|
|Lr | --> |Md | + |He |
|256| |252| | 4|
-----
|101| | 0| |100|
|Md | + |e- | --> |Fm |
|252| | 0| |252|
-----
| 2| | 98| |100|
|He | + |Cf | <-- |Fm |
| 4| |248| |252|
-----
|...|
104 - Rf - rutherfordium
----------------------
The Dubna lab in USSR produced rutherfordium in 1966, followed by
UC-Berkeley in 1969. There broke out a dispute over the discovery
credit and right to name the new element. The contentions lasted for
several future element claims, to be known as the Trandfrmium War.
Russia called it kurchatovium, Ku, and refused to recognize the
American name of rutherfordium, Rf.
In 1993 IUPAC allowed that both labs deserve the discovery credit
but the name was left open. In 1997 it formally established
rutherfordium, Rf, as the name.
The Dubna reaction beamed plutonium with neon:
| 94| | 10| |104| | 0|
|Pu | + |Ne | --> |Rf | + 3 |n |
|242| | 22| |260| | 1|
-----
|104|
|Rf | --> fission
|260|
The UC-Berkeley work used this chain:
| 98| | 6| |104| | 0|
|Cf | + |C | ---> |Rf | + 4 |n |
|249| | 12| |257| | 1|
-----
|104| |102| | 2|
|Rf | --> |No | + |He |
|257| |253| | 4|
-----
|102| |100| | 2|
|No | --> |Fm | + |He |
|253| |249| | 4|
----
| 99| | 0| |100|
|Es | <-- |e- | + |Fm |
|249| | 0| |249|
-----
|...|
105 - Db - dubnium
----------------
This is the second battle in the Transfermium War between Dubna
and Berkeley. Dubna claimed creation of dubnium in 1968 and suggested
name nielsbohrium. Berkeley created it in 1970 and suggested name
hahnium, Ha.
IUPAC in 1993 gave both sides the discovery credit but held off
from the name. In 1997 it set the name dubnium. Db.
The Dubna reaction is:
| 95| | 10| |105| | 0|
|Am | + |Ne | --> |Db | + 5 |n |
|243| | 22| |260| | 1|
-----
|105| |103| | 2|
|Db | --> |Lr | + |He |
|260| |256| | 4|
-----
|103| |101| | 2|
|Lr | --> |Md | + |He |
|256| |252| | 4|
-----
|100| | 0| |101|
|Fm | <-- |e- | + |Md |
|252| | 0| |252|
-----
|100| | 98| | 2|
|Fm | --> |Cf | + |He |
|252| |248| | 4|
-----
|...|
The UC-Berkeley lab tried:
| 98| | 7| |105| | 0|
|Cf | + |N | --> |Db | + 4 |n |
|249| | 15| |260| | 1|
-----
|105| |103| | 2|
|Db | --> |Lr | + |He |
|260| |256| | 4|
-----
|103| |101| | 2|
|Lr | --> |Md | + |He |
|256| |252| | 4|
-----
|100| | 0| |101|
|Fm | <-- |e- | + |Md |
|252| | 0| |252|
-----
|100| | 98| | 2|
|Fm | --> |Cf | + |He |
|252| |248| | 4|
-----
|...|
In this peculiar instance the same isotope was repoduced by both
labs. In the sample chains I show for previous elements different
isotopes were created. As long as the lab made any one confirmed
isotope it becomes one of the labs that found the new element.
106 - Sg - seaborgium
-------------------
Berkeley lab and Livermore lab jointly created seagorhium in 1974,
The US labs proposed seagorgium to honor Glenn Seaborg, the leader of
the effort. USSR vigorously objected on grounds that elements should
not be named for living persons, thus opening the next battle in the
Tranfermium War.
Two previous new elements were already named for living persons:
fermium for Fermi and einsteinium for Einstein. They died before these
elements were publicly announced.
The Berkeley-Livermore event chain is
| 98| | 8| |106| | 0|
|Cf | + |O | --> |Sg | + 4 |n |
|249| | 18| |263| | 1|
-----
|106| |104| | 2|
|Sg | --> |Rf | + |He |
|263| |259| | 4}
-----
|104| |102| | 4|
|Rf | --> |No | + |He |
|259| |255| | 2|
-----
| 2| |100| |102|
|He | + |Fm | <-- |No |
| 4| |251| |255|
-----
|100| | 0| | 99|
|Fm | + |e- | --> |Es |
|251| | 0| |251|
-----
|...|
IUPAC in 1993 assigned discovery credt to the Berkeley-Livermore
group. IUPAC in 1997 allowed seaborgium, Sg, for element 106.
Glenn Seaborg was the only person on Earth whose postal address
was composed entirely of names of elements! You could address mail to
him at:
+----------------------------------------------------------+
| Leonid Brezhnev ~~~~~~~~~ |
| The Kremlin ~ U S ~ |
| Moscow, USSR ~ 1st ~ |
| ~ Class ~ |
~~~~~~~~~ |
| Seaborgium |
| Lawrencium |
| Berkelium |
| Californium |
| Americium |
| Tellurium |
| Helium |
| |
+----------------------------------------------------------+
This means: 'Dr Glenn Seaborg; Lawremce Lab; Berkeley; California;
United States; Earth; Solar system'. The post office duly delivered
such mail correctly.
107 - Bh - bohrium
----------------
The atomic lab in Darmstadt, Germany, first produced bohrium in
1981, after several weak results at Dubna since 1976. The Transfermium
War continued with bohrium but not so severely as before. There were
no real contenders for the discovery.
In 1993 IUPAC awarded discovery to Darmstadt. The lab proposed
name nielsbohrium, which raised dispute becuase of its length and use
of the person's first name. IUPAC in 1997 gave name bohrium with
symbol Bh.
Darmstadt beamed a bismuth target with chromium in this chain:
| 83| | 24| |107| | 0|
|Bi | + |Cr | --> |Bh | + |n |
|209| | 54| |262| | 1|
-----
|107| |105| | 2|
|Bh | --> |Db | + |He |
|262| |258| | 4|
-----
|105| | 0| |104|
|Db | + |d- | --> |Rf |
|258| | 0| |258|
-----
|104|
fission <-- |Rf |
|258|
108 - Hs - hassium
----------------
The Dubna lab probably produced hassium in 1983 but the work was
too loose to be convincing. It was useful for other labs to continue
the hunt, like at Darmstadt.
The Darmstadt lab first produced hassium in 1984 by beaming iron
at a lead target. The lab proposed hassium for the name.
IUPAC in 1993 credited both Darmstadt and Dubna for the discovery.
In 1997 IUPAC accepted hassium, Hs, for element 108.
The Darmstadt reaction chain is
| 82| | 26| |108| | 0|
|Pb | + |Fe | --> |Hs | + |n |
|208| | 58| |265| | 1|
-----
|108| |106| | 2|
|Hs | --> |Sg | + |He |
|265| |261| | 4|
-----
|106| |104| | 2|
|Sg | --> |Rf | + |He |
|261| |257| | 4|
-----
| 2| |102| |104|
|He | + |No | <-- |Rf |
| 4| |253| |257|
-----
| 2| |100| |102|
|He | + |Fm | <-- |No |
| 4| |249| |253|
-----
|100| | 0| | 99|
|Fm | + |e- | + |Es |
|249| | 0| |249|
-----
|...|
109 - Mt - meitnerium
-------------------
Darmstadt in 1982 first created mritnerium, There were no
competitor claims and the lab proposed name meitnerium, Mt, with no
objections.
IUPAC awarded credit to Darmstadt in 1993. In 1997 is formally
named the element meitnerium, Mt.
The decay chain is
| 83| | 26| |109| | 0|
|Bi | + |Fe | --> |Mt | + |n |
|209| | 58| |266| | 1|
-----
|109| |107| | 2|
|Mt | --> |Bh | + |He |
|266| |262| | 4|
-----
|107| |105| | 2|
|Bh | --> |Db | + |He |
|262| |258| | 4|
-----
| 2| |103| |105|
|He | + |Lr | <-- |Db |
| 4| |254| |258|
-----
| 2| |101| |103|
|He | + |Md | <-- |Lr |
| 4| |250| |254|
-----
|101| | 0| |100|
|Md | + |e- | --> |Fm |
|250| | 0| |250|
-----
|100| | 98| | 2|
|Fm | --> |Cf | + |He |
|250| |246| | 4|
-----
|...|
The confirmation and eventual naming of element 109 ended the
Transfermium War.
110 - Ds - darmstadtium
---------------------
Darmstadt in 1994 first produced darmstadtium by beaming nickel at
a laed target. It suggested wixhausium, Wi, after the town outside
Darmstadt where the lab is located. It quickly changed mind and sent
in darmstadtium,Ds, for the central city.
IUPAC in 2001 credited Darmstadt for the dsicovery and in 2003
accepted name darmstadftium, Ds.
The Darmstadt decay chain is
| 82| | 28| |110| | 0|
|Pb | + |Ni | --> |Ds | + |n |
|208| | 64| |271| | 1|
-----
|110| |108| | 2|
|Ds | --> |Hs | + |He |
|271| |267| | 4|
-----
|108| |106| | 2|
|Hs | --> |Sg | + |He |
|267| |263| | 4|
-----
|106|
|Sg | --> fission
|263|
111 - Rg - roentgenium
--------------------
Roentgenium was first made at Darmstadt lab in 1994 be beaming a
bismuthtarget with nickel. Ther were no competing claims.
In 2003 IUPAC gave Darmstadt the discovery credit and the lab
suggested name roentgenium, Rg. This was acceptedby IUPAC in 2004.
The Darmstadt reactin chain is
| 83| | 28| |111| | 0|
|Bi | + |Ni | --> |Rg | + |n |
|209| | 64| |272| | 1|
-----
|111| |109| | 2|
|Rg | --> |Mt | + |He |
|272| |268| | 4|
-----
|109| |107| | 2|
|Mt | --> |Bh | + |He |
|268| |264| | 4|
-----
|107| |105| | 2|
|Bh | --> |Db | + |He |
|264| |260| | 4|
-----
| 2| |103| |105|
|He | + |Lr | <-- |Db |
| 4| |256| |260|
-----
| 2| |101| |103|
|He | + |Md | <-- |Lr |
| 4| |252| |256|
-----
|100| | 0| |101|
|Fm | <-- |e- | + |Md |
|252| | 0| |252|
-----
|100| | 98| | 2|
|Fm | --> |Cf | + |He |
|252| |248| | 4|
-----
|...|
112 - Cn - copernicium
--------------------
In 1996 the Darmstadt lab produced copernicium by beaming a lead
target with zinc. The claim was dismissed due to erratic description
of the decay products. Darmstadt repeated the work over the next
several years.
One difficulty was that some of the decay nuclei had multiple
decay modes which were not yet fully documneted. Since each instance,
yelding but one or two atoms of copernicium, could procede along any
set of these modes, the reaction chain followed discordant paths.
In 2009 IUPAC confirmed Darmstadt as discoverer of copernicium.
and officiated the name in 2010.
The Darmstadt decay chain, using only the currently known
dominant decay methods along the way, is
| 82| | 30| |112| | 0|
|Pb | + |Zn | --> |Cn | + |n |
|208| | 30| |277| | 1|
-----
|112| |110| | 2|
|Cn | --> |Ds | + |He |
|277| |273| | 4}
-----
|110| |108| | 2|
|Ds | --> |Hs | + |He |
|273| |269| | 4|
-----
|108| |106| | 2|
|Hs | --> |Sg | + |He |
|269| |265| | 4|
-----
| 2| |104| |106|
|He | + |Rf | <-- |Sg |
| 4| |261| |265|
-----
| 2| |102| |104|
|He | + |No | <-- |Rf |
| 4| |257| |261|
-----
| 2| |100| |102|
|He | + |Fm | <-- |No |
| 4| |253| |257|
-----
|100| | 0| | 99|
|Fm | + |e- | --> |Es |
|253| | 0| |253|
-----
|...|
113 - Uut - ununtrium
-------------------
As at mid 2011 there is no confirmed discovery for element 113.
The RIKEN lab in Japan and the joint Dubna-Livermore labs both report
detection of element 113. but with inconsistent details.
Names suggested by the RIKEN lab are japonium and rikenium. Dubna
proposes becquerelium.
114 - Uuq - ununquadium
---------------------
The Dubna lab formed element 114 in 2002, after earlier tries that
could not be verified. It worked with a plutonium target beamed by
calcium. Livermore lab, and others, repeated the work with better
detail to positively create Uuq.
In 2011 IUPAC confimed the discovery to both Dubna and lIvermore.
Dubna then suggested name flerovium. As at mid 2011 the name is not
official.
The Dubna decay chain is
| 94| | 20| |114| | 0|
|Pu | + |Ca | --> |Uuq| + 3 |n |
|242| | 48| |287| | 1|
-----
|114| |112| | 2|
|Uuq| --> |Cn | + |He |
|287| |283| | 4|
-----
|112| |110| | 2|
|Cn | --> |Ds | + |He |
|283| |279| | 4|
-----
|110| |108| | 2|
|Ds | --> |Hs | + |He |
|279| |275| | 4|
-----
| 2| |106| |108|
|He | + |Sg | <-- |Hs |
| 4| |271| |275|
-----
| 2| |104| |106|
|He | + |Rf | <-- |Sg |
| 4| |267| |271|
-----
|104|
fission <-- |Rf |
|267|
115 - Uup - ununpentium
---------------------
As at mid 2011 there is no discovery claim for element 115.
116 - Uuh - ununhexium
--------------------
Dubna and Livermore labs worked together to form element 116 by
beaming a curium target with calcium. It so happens that the decay
chain after the creation of Uuh-291 is the same as for element-114.
In 2011 IUPAC awarded credit to both Livermore and Dubna. The labs
did not as at mid 2011 offer a name and IUPAC did not itself establish
a name.
| 96| | 20| |116| | 0|
|Cm | + |Ca | --> |Uuh| + 2 |n |
|245| | 48| |291| | 1|
-----
|116| |114| | 2|
|Uuh| --> |Uuq| + |He |
|291| |287| | 4|
-----
|114| |112| | 2|
|Uuq| --> |Cn | + |He |
|287| |283| | 4|
-----
| 2| |110| |112|
|He | + |Ds | <-- |Cn |
| 4| |279| |283|
-----
|110| |108| | 2|
|Ds | --> |Hs | + |He |
|279| |275| | 4|
-----
| 2| |106| |108|
|He | + |Sg | <-- |Hs |
| 4| |271| |275|
-----
| 2| |104| |106|
|He | + |Rf | <-- |Sg |
| 4| |267| |271|
-----
|104|
fission <-- |Rf |
|267|
The similarity of the two reaction chains strengthened the both
for the two elements 114 and 116 together rather as separate claims.
117 - Uus - ununseptium, and higher
---------------------------------
As at mid 2011 there are nodiscovery claims for elements 117 and
higher. They are under hunt at the four main nuclear labs at Dubna,
Russia; Livermore & Berkeley, United States; Darmstadt, Germany; and
RIKEN, Japan.
Conclusion
--------
The discovery of new chemical elements is no longer the
traditional uncovering of them from natural sources. The new elements,
higher than fermium, are all artidicially made in atomic laboratories
thru beaming a target atom wiwith an other atom. The two atoms merge
and fuse into a new atom, hopefully the one neede for a disocvery.
The new element is not directly indetified because its propertis
are unknown, preventing a positive detection method to be applied. The
new element is inferred by examining its decay nuclei, which should be
among known nuclei with established properties.
Usually there is one decay mode for a given isotope. Commonly
among the higher numbered elements there are several methods of decay.
The mixture of these different decay modes, plus those fromother
isotopes created in the reaction makes it a real skill and art to
confidently home in on the parent, new, nucleus.
I give in this article only one of the usually many branches of
the decay chain for each of the transferium atoms. Other references
can offer different paths of decay, whether in the same reaction or
fromother experiments and from other labs.
There can be no threat or hazard to the public from creting these
elements, other than the usual and ordinary cautions surrounding
atomic lab work. The elements are made in single atom counts, one to
perhaps twenty in all the world. They all have short delay times or
halflifes, ensuring that they will vanish forever in a few minutes.
The long lag between a discovery claim and confirmation and then
to naming is the worikings of peer review of scientific work and the
extreme complexity of the experimental data. It just takes time to
study the work and see what really happened.