Investigation of low-hydrated metal(II) nitrates. Syntheses and crystal structures of Zn(NO <sub/>3</sub> ) <sub/>2</sub> · H <sub/>2</sub> O and M(II)(NO <sub/>3</sub> ) <sub/>2</sub> · 2 H <sub/>2</sub> O (M = Mg, Mn, Co, Ni)Wildner, Manfred; Giester, Gerald; Lengauer, Christian L.; Zemann, Josef · Zeitschrift für Kristallographie · 2012