Finally c p , α α , and κ κ T are all infinite on the curve T = 2 a ( v − − b ) 2 / ( R v 3 ) = T c ( 3 v r − − 1 ) 2 / ( 4 v r 3 ) . This curve, called the spinodal curve, is defined by κ κ T − − 1 = 0 , and is discussed at length in the next section.