An Easily Constructed Monocapped Antiprism Model Shukichi Yamana Faculty of General Education, Kinki University, Kowakae, Higashi Osaka 577, Japan
A model of a m o n o c a n ~ e dantinrism which is useful for teaching stereochemistry (for example, of t h e lanthanum ditelluride LaTeJl can he made easily by usinn a sealed, empty envelope.- he steps (illustrated i n t h e Figure) a r e given below. (1) The first figure shows the starting configuration which is produced by steps 1-8 of a previously published a r t i ~ l e . ~ (2) The intersection of the left-hand side of the envelope and the extension of the line GI is marked M. (3) A horizontal line perpendicular to the left-hand side of the envelope a t M is drawn so that it crosses the lines (Dl,(0,and (E),and the right-hand side of the envelope a t N, 0 , P, and Q, respectively. (4) The upper part of the envelope is cut off along the line MQ. (5) On the hack of the envelope, the points corresponding to N, 0 , and P are marked N*, O', and Pa,respectively. (6) Oblique lines are drawn to shade four triangles (MI0 and OKQ on the front; and QK'O* and O*I*M on the back). (7) The envelope is folded both backward and forward along the lines JL, FG (i.e., FG*), GH (i.e., G'H), MG (i.e., MG*), OH
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Journal of Chemical Education
(i.e., O*H), OF (i.e., O'F), QG (i.e., QG*), NI (i.e., N'I'), OG (i.e., O'G*), and PK (i.e., P'K*). (8) The right- and left-hand sides of the envelope are pushed toward each other so that four lines (FG, GH, HG*, and G'F) form four sides of a square. (9) Faces marked with the letter a are brought together and stacked in the order given by their numerals. Then, the face having the largest numeral, ar, is outside and the others a,-a3 are folded inside. The sides are taped to produce a base of the model given in the title. (10) The left- andright-hand sides of the upper part of the envelope are oushed toward each other so that four lines (IK. KK'. K*I:. and I*I) form four sides of a sauare ( 1 11 Four points M,O,Q, and 0' are puihed togrther and shaded crrnsrd triangles (h110, OKQ. QK'O', and O'I'M) nre folded inside. The sldes are taped toge~herto pruduce the model desired
' Wang, R.; Steinfink,H.: Bradley, W. F. hwg. Chem. 1966, 5, 142. Yamana, S. J. Chem. Educ. 1988,65, 1072.
