Additionally suitable gases may include reactive gases or {HEAD ~ gases} with reactive components, or {TAIL ~ combinations} thereof 
Additionally suitable gases may include reactive gases or { HEAD ~ gases } with reactive components , or { TAIL ~ combinations } thereof
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH