International
Tables for
Crystallography
Volume A
Space-group symmetry
Edited by Th. Hahn

International Tables for Crystallography (2006). Vol. A. ch. 10.1, pp. 800-801

Table 10.1.4.3 

Th. Hahna* and H. Klappera

a Institut für Kristallographie, Rheinisch-Westfälische Technische Hochschule, Aachen, Germany
Correspondence e-mail:  hahn@xtl.rwth-aachen.de

Table 10.1.4.3 | top | pdf |
The two icosahedral point groups

General, special and limiting face forms and point forms, oriented face- and site-symmetry symbols, and `initial' values of (hkl) and x, y, z (see text).

235 I   [Scheme scheme58]
60 d 1 Pentagon-hexecontahedron (hkl)
      Snub pentagon-dodecahedron (= pentagon-dodecahedron + icosahedron + pentagon-hexecontahedron) x, y, z
      [\left\{\matrix{\hbox{Trisicosahedron}\hfill\cr Pentagon\hbox{-}dodecahedron\ truncated\ by\ icosahedron\hfill\cr (\hbox{poles between axes 2 and 3})\hfill\cr \cr\hbox{Deltoid\hbox{-}hexecontahedron}\hfill\cr Rhomb\hbox{-}triacontahedron\ \&\ \hfill\cr pentagon\hbox{-}dodecahedron\ \&\ icosahedron\hfill\cr (\hbox{poles between axes 3 and 5})\hfill\cr \cr \hbox{Pentakisdodecahedron}\hfill\cr Icosahedron\ truncated\ by\hfill\cr pentagon\hbox{-}dodecahedron\hfill\cr (\hbox{poles between axes 5 and 2)}\hfill\cr}\right.] [\matrix{(0kl)\hbox{ with } |l| \lt 0.382 |k|\hfill\cr 0,y,z\ with\ |z| \lt 0.382 |y|\hfill\cr \cr\cr (0kl)\hbox{ with }0.382 |k| \lt |l| \lt 1.618 |k|\hfill\cr 0,y,z\ with\ 0.382 |y| \lt |z| \lt 1.618 |y|\hfill\cr\cr\cr\cr (0kl)\hbox{ with }|l| \gt 1.618 |k|\hfill\cr 0,y,z\ with\ |z| \gt 1.618 |y|\hfill\cr\cr\cr}]
30 c 2.. [\!\matrix{\hbox{Rhomb-triacontahedron}\hfill\cr Icosadodecahedron\ (\!= pentagon\hbox{-}\hfill\cr dodecahedron\ \&\ icosahedron)\hfill\cr}] [\!\matrix{(100)\hfill\cr x,0,0\hfill\cr\cr}]
         
20 b .3. [\!\matrix{\hbox{Regular icosahedron}\hfill\cr Regular\ pentagon\hbox{-}dodecahedron\hfill\cr}] [\!\matrix{(111)\hfill\cr x,\;x,\;x\hfill\cr}]
12 a ..5 [\!\matrix{\hbox{Regular pentagon-dodecahedron}\hfill\cr {Regular\ icosahedron}\hfill\cr}] [\left.\matrix{(01\tau)\hfill\cr 0,y,\tau y\hfill\cr}\right\} \hbox{ with } \tau = {\textstyle{1 \over 2}}(\sqrt{5} + 1) = 1.618]
Symmetry of special projections  
[\matrix{\hbox{Along } [001]&&&\hbox{Along } [111]&&&\hbox{Along } [1\tau 0]\cr 2mm&&&3m&&&5m}]  
[\matrix{m\bar{3}\bar{5}\hfill\cr\cr\displaystyle{2 \over m}\bar{3}\bar{5}\hfill\cr}] [I_{h}]   [Scheme scheme59]
120 e l Hecatonicosahedron or hexaicosahedron (hkl)
      Pentagon-dodecahedron truncated by icosahedron and by rhomb-triacontahedron x, y, z
60 d m.. [\left\{\matrix{\hbox{Trisicosahedron}\hfill\cr Pentagon\hbox{-}dodecahedron\ truncated\ by\ icosahedron\hfill\cr \hbox{(poles between axes 2 and }\overline{3})\hfill\cr \cr \hbox{Deltoid-hexecontahedron}\hfill\cr Rhomb\hbox{-}triacontahedron\ \& \ pentagon\hbox{-}dodecahedron\ \& \hfill\cr icosahedron\hfill\cr \hbox{(poles between axes }\overline{3} \hbox{ and } \overline{5})\hfill\cr \cr \hbox{Pentakisdodecahedron}\hfill\cr Icosahedron\ truncated\ by\ pentagon\hbox{-}dodecahedron\hfill\cr \hbox{(poles between axes }\overline{5} \hbox{ and } 2)\hfill\cr}\right.] [\matrix{(0kl) \hbox{ with } |l| \;\lt\; 0.382 |k|\hfill\cr 0,y,z\ with\ |z| \;\lt\; 0.382 |y|\hfill\cr \cr\cr (0kl) \hbox{ with } 0.382 |k| \;\lt\; |l| \;\lt\; 1.618 |k|\hfill\cr 0,y,z\ with\ 0.382 |y| \;\lt\; |z| \;\lt\; 1.618 |y|\hfill\cr \cr\cr\cr (0kl) \hbox{ with } |l| \;\gt\; 1.618 |k|\hfill\cr 0,y,z\ with\ |z| \;\gt\; 1.618 |y|\hfill\cr\cr}]
30 c 2mm.. Rhomb-triacontahedron (100)
      Icosadodecahedron (= pentagon-dodecahedron [\&] icosahedron) x, 0, 0
20 b 3m (m3.) Regular icosahedron (111)
      Regular pentagon-dodecahedron x, x, x
12 a 5m (m.5) [\!\matrix{\hbox{Regular pentagon-dodecahedron}\hfill\cr Regular\ icosahedron\hfill\cr}] [\left.\matrix{(01\tau)\hfill\cr 0,y,\tau y\hfill\cr}\right\} \hbox{ with }\tau = {1 \over 2}(\sqrt{5} + 1) = 1.618]
Symmetry of special projections  
[\matrix{\hbox{Along }[001]&&\hbox{Along }[111]&&\hbox{Along }[1\tau 0]\cr 2mm&&6mm&&10mm\cr}]