T. Kitazawa et al., SPIN-CROSSOVER BEHAVIOR OF THE COORDINATION POLYMER FE-II(C5H5N)(2)NI-II(CN)(4), Journal of materials chemistry, 6(1), 1996, pp. 119-121
The iron(II) spin state of Fe(C5H5N)(2)Ni(CN)(4) changes from paramagn
etic to diamagnetic when the temperature is lowered, while that of Fe(
NH3)(2)Ni(CN)(4) . 2C(6)H(6) does not.