The thermosetting material contains {TAIL ~ a refractory metal} capable of reacting with boron to form {HEAD ~ a metal boride} 
The thermosetting material contains { TAIL ~ a refractory metal } capable of reacting with boron to form { HEAD ~ a metal boride }
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD