thumbnail ~ k e t c h e ~ Group Names W. Conard Fernelius Kent State University, Kent, OH 44242
Every person has a given and a family name. Chemistry makes frequent use of names for individual elements and compounds, but it also has need for family or group names. The most common use of group names is the division of elements into metals and nonmetals. However, the division is not sharp as evidenced by the intermediate group of metalloids. Another broad group name is earth, much used in the days before chemistry was truly a science and refers to such oxides as those of iron and aluminum which are recognized by certain characteristic properties and trivalence. We encounter avestige of that name in alkaline earths (Ca, Sr, Ba) today. These were intermediate between the alhalls and the earths. If one wishes to distinguish the elements from their compounds, one says alhall and alkalcne earth metals (or elements). once more in the group name . The word earth annears .. rare earths. Other old and common group names >e halogen (Greek ha1 or salt) (F, C1, Br, I) and their salts, the halides. Somewhat less well known hut reasonably common is chalcogens (Latin for calx) ( 0 , S, Se, Te) and chalcogenides. When the group zero elements were discovered, they were grouped under the name rare Rases. Since these are no longer considered to be rare, the term rnert gases is often used. The preparation of compounds of a few of the rare gases cast a shadow on the word inert, but there is no agreement on a term which implies reluctant-to-form-compounds-but-not-impossible although some consider noble suitable. The usage of words does not remain static hut changes with time. These are chanees in both popularity and meaning. As the understanding offuudamentd ;hemistry increases (laws, theory, etc.) it becomes necessary to have more precise terms. In the nature of language, i t is far easier to broaden the meaning of terms than it is to restrict meaning. Hence chemists are continually creating new words to obtain more precise meanings. When V. Goldschmidt desired a term for
edited by MARYVIRGINIAORNA, 0.S.U College of New Rochelle New Rochelle, NY 10801
along with Th, Pa, and U, have become known as actinides. Some would prefer lanthanoids and actinoids to avoid the possible implication that these are binary compounds-the usual significance of -ide. Various fields of endeavor have focused attention on the binary compounds of N, P, As, and Sb and of C, Si, Ge, and Sn. The first group has been designated pnicogens (Greek pnignos, snffocation).while merylides (origin obscure) has been suggested for the second group. Objection has been raised to these terms because the meaning of the terms is evident only to a few modern day scholars. To he sure, the terms are hased on oerfectlv. eood Greek or Latin words (standard practice in science), but unfortunately modern chemists are not particularly outstanding as students of ancient languages. The development of chemical nomenclature is in the direction of simplification and generalization rather than placing an ever increasing burden on memory. One needs a general system for-designatine groups .. . of related elements and their compounds. The suggestion is to use the group number: tetrels and tetrelldes (C, Si, Ge, Sn), pentels andpentelrdes (N, P, As, Sb), etc. Chemists do know Greek numbers! Why should we be so concerned with names? Why not use the expression Group VB elements or binary compounds, etc.? Unfortunately, N, P, As, Sh, and Bi are designated both as VA and VB, etc., and there is no agreement-but that is another story! Notes 1) In the matter of group names, it is odd haw widely used they are without anyone seemingly conscious o f their origin. Even historians are of no help. There is no mention of the origin of halogen in Crossland, and chalcogen is not mentioned. The same situation is true for M. E. Weeks "Discovery of the Chemical Elements." 2) There are only two references that can be added to the account of group names. They are IUPAC Commissionon the Nomenclatureof Inorganic Chemistry, ''Nomenclatureof Inorganic Chemistry, DefinitiveRules 1970; Butterwarthr, London,p. 10. 197L: h i e Appl Chem.28 (1),10 (1971).
Fernelius. W. C., Loening. K., and Adams, A. M., J. CHEM. EDIIC.,48, 595, 730 (19711.
1 Editor's Note
related elements with atomic numbers greater than 92, these,
140
Journal of Chemical Education
Conard Fernelius and Warren Powell have prepared a full account of the use (and misuse)af Aand B in designatinggroupsin the periodic table. This article appeared in the "Textbook Forum" feature of Mls . ~ U R N A L[59, 504 (1982)).
