 Solid xenon changes from face @-@ centered cubic ( fcc ) to hexagonal close packed ( hcp ) crystal phase under pressure and begins to turn metallic at about 140 GPa , with no noticeable volume change in the hcp phase . It is completely metallic at 155 GPa . When metallized , xenon looks sky blue because it absorbs red light and transmits other visible frequencies . Such behavior is unusual for a metal and is explained by the relatively small widths of the electron bands in metallic xenon . 
 Solid xenon changes from face @-@ centered cubic ( fcc ) to hexagonal close packed ( hcp ) crystal phase under pressure and <a href='uninflect' title='1'><mark>begins</mark></a> to turn metallic at about 140 GPa , with no noticeable volume change in the hcp phase . It <a href='drop_aux' title='2'><mark>is</mark></a>completely metallic at 155 GPa . When metallized , xenon <a href='uninflect' title='3'><mark>looks</mark></a> sky blue because it <a href='uninflect' title='4'><mark>absorbs</mark></a> red light and <a href='uninflect' title='5'><mark>transmits</mark></a> other visible frequencies . Such behavior <a href='drop_aux' title='6'><mark>is</mark></a>unusual for a metal and is explained by the relatively small widths of the electron bands in metallic xenon . 
Solid xenon changes from face @-@ centered cubic ( fcc ) to hexagonal close packed ( hcp ) crystal phase under pressure and begin to turn metallic at bout 140 GPa , with no noticeable volume change in the hcp phase . It completely metallic at 155 GPa . When metallized , xenon look sky blue because it absorb red light and transmit other visible frequencies . Such behavior unusual fa a metal and is explained by the relatively small widths of da electron bands in metallic xenon .