P2_1/c        4        0.00000   0.00000   0.00000
  1.  0.  0.  0.  1.  0.  0.  0.  1. -1.  0.  0.  0.  1.  0.  0.  0. -1.
 -1.  0.  0.  0. -1.  0.  0.  0. -1.  1.  0.  0.  0. -1.  0.  0.  0.  1.
 0.00000 0.00000 0.00000 0.00000 0.50000 0.50000 0.00000 0.00000 0.00000
 0.00000 0.50000 0.50000

	x	y	z
	-x	1/2+y	1/2-z
	-x	-y	-z
	x	1/2-y	1/2+z