Fast N(D-2) atoms colliding with CH4 at 10-200 eV(CM) yield CH(A,B), NH(A) and H(n greater than or equal to 4) emission. From 10 to 50 eVCM the CH yield decreases, exceeding greatly that for NOS) and N+((3)p) + CH4 collisions. This indicates N(D-2) insertion. Above 50 eV(CM) the CH yield increases again, approaching the values found with N(S-4) and N+(P-3). Here the CH formation is chemically unspecific ('shattering'). The NH(A) yield decreases monotonically for all three projectiles. N(D-2) insertion is here unimportant, in contrast to NH(X) from N(D-2) + CH4. At E-CM >50 eV(CM), all projectiles give NH(A) according to the 'billiard ball' model. (C) 2003 Elsevier B.V. All rights reserved.