Vol. 68
288
COMMUNICATION TO THE EDITOR HOMOTATTIC SURFACE-A SUGGESTED tively homogeneous.” Some more precise term is needed, specific to the aspects of surface homogeneNEW WORD ity studied by the physical chemist. Sir: We accordingly suggest the term homotattic The purpose of this letter is to suggest precise (Gr. tattein, to draw up in orderly array). A terms for discussion of certain surface phenomena. Taylor and others‘ have demonstrated that solid homotattic surface is the surface of a sub-microscopic surfaces are irregular in construction. More re- patch or region, part of a larger surface, which acts cent work, notably on surface ad~orptioii,~.3.4.6,6as if its structure were uniform and homogeneous. A crystal surface of, say, sodium chloride may has indicated that a solid surface sometimes includes, or may consist of, submicroscopic patches contain (or may perhaps consist of) a single homotattic surface, which would normally be the { 100) or regions of regular and uniform construction. These regular and uniform patches are generally surface planes. Another sample, prepared under described in the literature as together forming a special conditions, may contain two homofattic surrelatively homogeneous surface : the relatively some- faces, the { 100)surface planes and the { 111 ] surface times being used in the sense of “somewhat” or planes. We do not exclude by this term the inter“rather,” sometimes indicating a comparison with pretation that homotattic surfaces may be evident the non-homogeneous portions of the same surface. by virtue of regularities in the surface energies, as The term relatively homogeneous is bad. Firstly, well as by crystallographic regularities. Two or it may offend the precisian to whom the idea of more crystallographic homotattic surfaces may behomogeneity does not admit of qualification. Sec- have as one energetically homotattic surface ondly, it conveys no notion of the scale of the toward certain adsorbates.7 Alternatively, a single phenomena to which it is applied: the surface of a crystallographic homotattic surface may behave sheet of paper, or of a macadam road, might i n as two or more energetically homotattic surfaces some contexts be reasonably described as “rela- toward certain adsorbates.* The term homotattic has not hitherto been ap(1) H. S. Taylor and S . C. Liang. J . A m . Chem. Soc., 69, 1306.2980 plied, as far as we know, in any other connection. (1947) (2) W. D. Harkins. G . Jura and E . H . Loeser; ibid., 68, 554 (19413). DEPARTMENTS O F ENGLISH A N D O F CHEMISTRY (3) Sydney Ross and G . E. Boyd, “New Observations on TwoDimensional Condensation Phenomena,” h l D DC Report No. 864, 1947. (4) L. C . Joyner and P. H. Emmett, J . Am. Chem. Soc.. 70, 2363 (1948). (5) C. Pierce and R. N . Smith, THISJ O U R K A64, L , 364 (1950). (6) M . H . Pdlcy. W. D . Schaeffer and W. R . Smith, ibid., 67, 469 (1953).
RENSSELAER POLYTECHNIC INSTITUTE CHRISSANFORD SYDNEY Ross TROY,N. Y. RECEIVED JANUARY 20, 1954 (7) For example, asbestos: see A. C. Zett.lemoyer, G . J . Young, J . J . Chessick and F. H. Healey, ibid., 67, 649 (1953). ( 8 ) For example, graphite: see G. Jura and D . Criddle, ibid., 66, 163 (1951).
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