Acronym	si
Name	snub icosahedron, compound of 10 oct (but not gissi)
	© ©
Circumradius	1/sqrt(2) = 0.707107
Inradius	1/sqrt(6) = 0.408248
Vertex figure	[34]
Dihedral angles (at margins)	between {3} and {3}:   arccos(-1/3) = 109.471221°
Confer	gissi   addasi
External links

It can be obtained by placing 10 oct, thought of as triagular antiprisms, within an ike (in each of the axial orientations) with base-faces oriented in the same way as for the ike.

A double cover of si occurs as special case of addasi.

Incidence matrix

 60 |  2  2 |  3  1 ||  1
----+-------+-------++---
  2 | 60  * |  1  1 ||  1
  2 |  * 60 |  2  0 ||  1
----+-------+-------++---
  3 |  1  2 | 60  * ||  1
  3 |  3  0 |  * 20 ||  1
----+-------+-------++---
♦ 6 |  6  6 |  6  2 || 10