Octahedral graph
= Octahedral graph
{title2=$K_{2,2,2}$}
The octahedral graph is the <graph> obtained from $K_6$ by removing a <perfect matching>; equivalently it is $K_{2,2,2}$. Its <chromatic number> is three, and it contains two vertex-disjoint <triangles in a graph>. A <complete bipartite graph> with a single additional internal edge cannot contain it: every triangle in that host uses the additional edge.