ChemMatters, OCTOBER 2008 13
helium, argon, and neon form a triad because
there are seven elements between helium and
argon and seven elements between argon and
neon. But, for example, nitrogen, phospho-
rus, and arsenic don’t form a triad because
nitrogen and phosphorus are separated by
seven elements, while phosphorus and arse-
nic are separated by 17 elements.
Scerri, who published an award-winning
book titled The Periodic Table: Its Story and
Its Significance, noticed that hydrogen (1),
fluorine (9), and chlorine (17) define a perfect
triad, but hydrogen is not located above flu-
orine—as would be required to make a triad.
So Scerri suggested moving hydrogen to the
second-to-last column of the table to obtain
a new triad (consisting of hydrogen, fluorine,
and chlorine).
Scerri also suggested moving the last two
columns to the left of the table, so that the
first period disappears and the table is now
made of pairs of periods, each pair being
of similar length. This new periodic table is
shown in Fig. 2.
The Periodic Spiral
Jeff Moran, a graphic designer and the
owner of Electric Prism, a software company
based in Woodstock, N.Y., has produced a
representation called the Periodic Spiral, in
which the elements are ordered in spirals.
The Periodic Spiral (Fig. 3), in which
the elements are represented as hexagons
(instead of squares), starts in the middle
with hydrogen and moves in circles clock-
wise from the inside out. Other than for the
first two elements (hydrogen and helium)
and the f block, a full loop corresponds to a
row in the traditional periodic table.
According to Moran, the Periodic Spiral
addresses three “serious flaws” in the
periodic table. “First, hydrogen has unique
properties unlike any other element in the
table, so, in essence, it belongs to none of
the 18 columns of the table,” Moran says.
“Second, the elements from each period
of the f block—called lanthanides and
actinides— have similar properties yet they
are not displayed in columns in the table.
Third, the table’s column-and-row design
doesn’t show the continuity between the
elements, which is better illustrated with a
spiral.”
To address these issues, Moran started
working on a spiral representation of the
elements in 1991 and pub-
lished it as a Web-based
application six years later
(available at www.periodic-
spiral.com/spiral.html).
The Chemical
Galaxy
Philip Stewart, a retired
teacher of ecology at the
University of Oxford in the
United Kingdom, created an
artistic representation of the
chemical elements, called the
Chemical Galaxy, (Fig. 4).
Stewart’s representation,
on which he worked during
three summers, from 2003
to 2005, looks like a galaxy
to reflect the fact that chemi-
cal elements are produced
in stars. The spokes of the
galaxy link elements with similar properties,
acting like the groups in the periodic table.
In the Chemical Galaxy, each element is
represented with a circle of a different color.
Stewart’s choice of colors runs through the
entire color spectrum, from violet for the
alkali metals (the group that includes lithium)
to red for the halogens (the group that
includes chlorine). Colorless grey was used
for the noble gases (the group that includes
neon), which participate very little in chemical
reactions, if at all.
In the middle of the Chemical Galaxy,
Stewart placed an additional element called
the neutronium, in which there are neither
protons nor electrons, but only neutrons. Sci-
entists have speculated that the neutronium
may be present inside very dense stars called
neutron stars.
Stewart hopes that the Chemical Galaxy
will be seen as a piece of art that conveys
the beauty and wonder of the universe. “I am
confident that other people will find other
ways of expressing ideas about the chemical
elements.”
Periodic table in
three dimensions
In 1977, I patented a version of the peri-
odic table in three dimensions called the
Periodic Round Table. In creating this table,
I used a modified version of the traditional
periodic table that addresses some of the
issues mentioned above.
The first scientist who modified the peri-
odic table this way was Charles Janet, a
French engineer and polymath. In 1929, he
proposed to move helium to the top of the
second column and then move the first two
columns (the s block) to the right and shift
them up one row (Fig. 5). Janet’s table has
eight rows, the first two consisting of a pair
of two elements each.
Figure 2. The long form of Scerri’s periodic table is more symmetric than the traditional periodic table.
The elements are grouped in four-column blocks on each side of the table and (except for the last
element, Uus), the number of same-length rows are gouped in pairs (one pair of rows with eight element
each, another pair of rows with 18 elements each, and a third pair of rows with 32 elements each).
Figure 3. In the Periodic Spiral, the elements start in the middle with
hydrogen and spiral clockwise from the inside out.
COPYRIGHT 1996-2008 JEFF MORAN
ELLIOTT KATZ