Synthesis and crystal structure of cesium nitratometalates(II), Cs-2[M(NO3)(4)] (M = Mn, Co, Ni, Zn)

Crystalline cesium nitratometalates(II), CS2[M(NO3)(4)] (M = Mn (I), Co (II ), Ni (III), and Zn (IV)) were synthesized hom M(NO3)(2). nH(2)O and CsNO3 by heating at 80-120 degrees C over 10-12 h. According to X-ray crystal str ucture analysis, the compounds are built from Cs+ cations and [M(NO3)(4)](2 -) anions. The latter differ by the type of metal coordination: a dodecahed ron for Mn in I (CN = 8, r(Mn-O) 2.24-2.37 Angstrom), a seven coordination for Co in II (CN = 4 + 3, r(Co-O) 2.03-2.16 Angstrom and 2.21-2.35 Angstrom ) and a tetrahedral distorted dodecahedron for Zn in IV (CN = 4 + 4, r(Zn-O ) 1.98-2.15 Angstrom and 2.38-2.72 Angstrom). Ni atom in III has a distorte d octahedral NiO6 environment provided by two unidentate and two bidentate NO3 groups with Ni-O distances of 2.01-2.14 Angstrom . The differences in m etal coordination are discussed in terms of valence electron configurations , ionic radii, and the packing effects.