The structures of the five-coordinate complexes Cu (terpy) X,[X= NCS-(I), Br-(II)] were determined (monoclinic, space group C2/c, Z= 4). The unit cell dimensions are a= 13.724 (3)[16.818 (3)] A, 6= 9.501 (1)[9.280 (lo)] A, c= 14.187 (3)[11.396 (7)] A, p= 110.54 (2)'[125.61 (4) O] for I [11], respectively. The unusual molecular geometry can be understood by following the pathway of the three e'normal modes in Dph symmetry. While usually the ...