  We study the structure of the rational motivic stable homotopy category over
general base schemes. Our first class of results concerns the six operations:
we prove absolute purity, stability of constructible objects, and
Grothendieck-Verdier duality for SH_Q. Next, we prove that SH_Q is canonically
SL-oriented; we compare SH_Q with the category of rational Milnor-Witt motives;
and we relate the rational bivariant A^1-theory to Chow-Witt groups. These
results are derived from analogous statements for the minus part of SH[1/2].
