JOURNAL OF CHEMICAL EDUCATION
492
0
A RELICAL PERIODIC TABLE WILLIAM E. RICE Experiment Incorporated, Richmond, Virginia
A
THREE-DIMENSIONAL representation of the periodic table can provide an additional coordinate to represent the difference between subgroups without disrupting the vertical sequence of elements in a whole group. This advantage is realized by the helical chart shown in the figure. I n this respect it is similar to but simpler than that proposed by Harkins and Hall' who arranged balls representing the chemical elements in a similar pattern in space. The chart consists of one vertical cylinder inside another, the two being tangent a t Group IV. The alkali metals occupy a vertical column on the inner cylinder; the copper subgroup is on the outer cylinder. The choice of Group IV as that group displaying least. difference between its subgroups is arbitrary but. not unreasonable. The lanthanide and actinide earths may be in exterior loops, as shown in the figure, or in interior loops, as used by C l a u ~ o n . ~ The chart is about 14 inches high and is made of 0.009-inch drawing paper. Each group is colored differently. The blocks on which the symbols of the elements are printed are sufficiently alike in size so that on a large scale one could include considerable written information about each element. The author will
HARKINS, WILW D., AND R. E. HALL,J. Am. Chem. Soc., 38, 169 (1916).
CLAWON, JENNIE E., J. CBEM,EDUC., 31,550 (1954).
be glad to supply interested readers with a pattern showing construction details.
