“…In this section we illustrate the effect of pressure on the following examples of different SCO behaviours: an abrupt spin transition, a gradual one and a pressure induced spin transition in a paramagnetic compound. For this purpose, we have chosen the following systems: [Fe(phen) 2 (NCS) 2 ] (phen: 1,10-phenanthroline) (1) [25], [Fe(PM-Aza) 2 (NCS) 2 ] (PM-Aza: (N-(2 -piridylmethylen)-4-azophenyl aniline)) (2) [26] and [Fe(abpt) 2 (NCS) 2 ] (abpt: 4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole) (3) [27] (figure 1). The two former compounds reveal an abrupt and a gradual spin transitions, respectively, at ambient pressure, whereas the third one is in the HS state over the whole range of temperatures under study.…”