Profundización

Nomenclatura de los Elementos Pesados

 
Número Atómico Nombre Sistemático Otro símbolo Otro símbolo
104
Unq
Db
Rf
105
Unp
Jl
Ha
106
Unh
Rf
Sg
107
Uns
Bh
Ns
108
Uno
Hn
Hs
109
Une
Mt
Mt

Debido a las disputas sobre el descubrimiento de los elementos más pesados, la Comisión de Nomenclatura de Química Inorgánica de la Unión Internacional de Química Pura y Aplicada (I.U.P.A.C.: International Union for Pure and Applied Chemistry) ha ideado una forma de nomenclatura sistemática, usando el latín. Cuando se descubre un nuevo elemento, su nombre se obtiene de la siguiente forma:

1. Se escribe el número atómico del elemento y se separan sus dígitos. Por ejemplo, para el hipotético elemento 115, se separa como 1-1-5.

2. Cada dígito se reemplaza por el nombre latino sistemático, de acuerdo con esta tabla:

    Número
    Nombre
    Número
    Nombre
    0
    nil
    5
    pent
    1
    un
    6
    hex
    2
    bi
    7
    sept
    3
    tri
    8
    oct
    4
    quad o cuad
    9
    enn

    En el ejemplo anterior, 1-1-5 nos conducirá a un un pent.

    3. Se juntan las palabras latinas y se añade la terminación -ium (en castellano se admite -io). Cuando bi o tri, se encuentran delante de -ium, la i se omite. Cuando enn se encuentra delante de nil, la última n se omite. Usando el mismo ejemplo, un un pent se transforma en ununpentium o ununpentio.

    4. El símbolo del elemento lo constituye la primera letra de cada una de las partes del nombre latino; la primera de ellas en mayúscula. El símbolo del elemento ununpentium es Uup.


    La misma Comisión de Nomenclatura ha aprobado, en agosto de 1997, una Recomendación para que se atribuyan nuevos nombres y símbolos a los elementos de número atómico 104 a 109. En versión española, son los siguientes:


    Número
    Nombre
    Símbolo
    104
    Rutherfordio
    Rf
    105
    Dubnio
    Db
    106
    Seaborgio
    Sg
    107
    Bohrio
    Bh
    108
    Hassio
    Hs
    109
    Meitnerio
    Mt

    Comentarios a la nomenclatura de los últimos elementos obtenidos

    (Elements Get Final Names)

    Tomado de New York Times

    After more than three years of sometimes acrimonious debate across the borders of many nations, an international body of chemists has reached a tentatuve agreement on the names to be bestowed upon six new chemical elements.

    The elements themselves, numbers 104 through 109 on the periodic table, were created by accelerator laboratories in the United States, Germany, and Russia over the last two decades and have little significance for non-scientists. Only a few atoms of each of these elements ever existed, and none survived after its creation for more than a few seconds before decaying radioactively into atomic debris.

    But the naming of a chemical element is influenced by national pride, professional rivalry and personal sensitivities; the picking of a single name can provoke as much back-room bickering and bargaining as the selection of an international beauty queen.

    The final court of appeals in this process is the International Union of Pure and Applied Chemistry, with member chemists from about 80 countries. Within the Union, factions representing the United States, Germany, Russia and several other nations have bitterly disagreed about namesl.

    A particularly sharp disagreement began three years ago when the Lawrence Berkeley Laboratory in Berkeley, Calif., backed by the American Chemical Society, tentatively named element 106 seaborgium, with the chemical symbol Sg. The name honored Glenn T. Seaborg, an American chemist and Nobel laureate, whose team created 10 new elements during and after World War II. In 1940, Seaborg's research group at Berkeley used an accelerator to make neptunium, the first element heavier than uranium (Before neptunium, the only element excisting solely as a laboratory product was technetium, which is No. 43 on the periodic table. It was created in 1937 by the fusion of atomic nuclei.).

    Seaborg's team went on to create plutonium, the element fueling the atomic bomb that destroyed Nagasaki, and eight other artificial elements. The American Chemical Society believed that international confirmation of the name seaborgium would be mere formality, but instead the international chemists' union provisionally named Element 106 rutherfordium honoring New Zealand-born physicist Ernest Rutherford.

    Adding insult to injury, in the view of the Berkeley group, the international union proposed naming element 104 dubnium, recognizing achievements in nuclear physics by the Joint Institute for Nuclear Research at Dubna, Russia. The Berkeley scientists and many other American physicists are skeptical of some of the claims made by the Dubna laboratory to having created new elements.

    After years of debate, the international union came up last month [Jan 1997] with a compromise list that most American chemists deem acceptable. David F. Eaton, a chemist at DuPont Corp. who headed the American delegation throughout the bargaining, said in an interview that all the American laboratories involved in the dispute were satisfied.

    Subject to confirmation by the union's members at a meeting in Geneva next August [1997], these will be the names of the six new elements: Element 104, Rutherfordium (symbol Rf); Element 105, Dubnium (symbol Db); Element 106, Seaborgium (symbol Sg); Element 107, Bohrioum (symbol Bh); Element 108, Hassium (symbol Hs); Element 109, Meitnerium (symbol Mt).

    (Bohrium takes its name from Niels Bohr, a Dane, who was a founder of quantum physics. Hassium is the Latin name for the German province Hesse, the seat of the laboratory where elements 109 and 110 were created, as well as a single atom of element 112 one year ago [1996]. Meitnerium is named for the Austrian-born physicist Lise Meitner.)

    Dropped from the union's previous list of provisional names are joliotium for Element 105, for the French physicicst Frederick Jolie-Curie, and hahnium for Element 108, honoring the German physicist Otto Hahn. "Fortunately, howerver," Eaton said, "we still have some unnamed elements to play with: Elements 110, 111 and 112."

    All three were created in Darmstadt, Germany, by the Society for Heavy Ion Research, and by tradition, the creator or discoverer of an element has the privilege of proposing its name. Conseguently, hahnium has a chance of rejoining the periodic table, and even the French joliotium might make into the pantheon.

    Final settlement of the issue will be a relief for the publishers of chemistry textbooks and scientific papers around the world; in the current confusion, five different versions of the periodic table are in circulation.

    "I think we're seeing real progress," Eaton said.

    Por MALCOLM W. BROWNE