Calcium complexation to derivatives of isonicotinic acid: [tetraaquabis(isonicotinamide)calcium] dichloride and tetraaquabis(isonicotinato)calcium, C12H20CaCl2N4O6 and C12H16CaN2O8

[Calcium(isonicotinamide)2(H2O)4]Cl2 (I), C12H20CaCl2N4O6: molecular weight = 427.3, triclinic, P1, a = 9.778(5), b = 8.623(4), c = 7.363(3) A, α = 115.09(3), β = 73.40(4), γ = 75.98(3)°, V = 489.3(3) A3, Z = 2, Dx = 1.450 g cm−3, F(000) = 222, λ(Mo Kα) = 0.71069 A, μ(Mo Kα) = 6.195 cm−1, 295 K, final R = 4.7%, Rw = 6.6% for 1985 observed reflections [I > 3σ(I)]. [Calcium(isonicotinate)2(H2O)4] (II), C12H16CaN2O8: molecular weight = 356.3, monoclinic, P21/a, a = 7.208(3), b = 36.368(28), c = 6.159(2) A, β = 104.74(3)°, V = 1561(1) A3, Z = 4, Dx = 1.516 g cm−3, F(000) = 744, λ(Mo Kα) = 0.71069 A, μ(Mo Kα) = 4.312 cm−1, final R = 6.4%, Rw = 8.3% for 1819 observed reflections [I > 3σ(I)]. In [calcium(isonicotinamide)2(H2O)4]Cl2, [C12H20CaCl2N4O6] (I), calcium is octahedrally coordinated to six oxygen atoms; four from water molecules and the carbonyl oxygen atoms of amide groups of two different isonicotinamide molecules. Amide and hetero-ring nitrogen atoms are unbound to calcium. Chloride atoms in the cell are hydrogen bonded to hydrogen atoms of amide groups. The seven coordinate calcium atom in calcium(isonicotinate)2(H2O)4, [C12H16CaN2O8] (II), is coordinated to four water molecule oxygen atoms, two oxygen atoms of a bidentate carboxylate group of one isonicotinate molecule and to the nitrogen atom of a second isonicotinate molecule.