Synthesis, Structure, and Magnetic Properties of the Oxalate-Based Bimetallic Ferromagnetic Chain {[K(18-crown-6)][Mn(H 2 O) 2 Cr(ox) 3 ]} ∞ (18-crown-6 = C 12 H 24 O 6 , ox = C 2 O 4 2 - )

The salt [K(18-crown-6)][Mn(H2O)2Cr(ox)3.0.5(18-crown-6) (1) has been prepared and structurally and magnetically characterized. It crystallizes in the P2(1)/c space group [a = 21.011(2) A, b = 11.265(2) A, c = 15.748(3) A, beta = 105.952(6) degrees , V = 3584(1) A3, and Z = 4] and contains [Mn(H2O)2Cr(ox)3]infinity chains connected through hydrogen bonding to form 2D anionic networks. The magnetic exchange is ferromagnetic [J = +2.23(2) cm(-1)] in the chain and also in between chains, reaching bulk ferromagnetic ordering below 3.5 K.