Sb4 tetrahedra

The group displays a remarkable number of allotropes of its members showing the trend from non-metallic forms through to metallic forms. Thus nitrogen has only the diatomic form phosphorus has a highly reactive form (brown), and a tetrahedral form P4 (white), forms based on broken tetrahedra P (red and violet), and a hexagonal layer-type lattice (black). Arsenic and antimony have the AS4 and Sb4 forms, which are less stable than the layer type in this case bismuth has the layer-lattice form only. 

---