Analogous Chain Selenite Chlorides Ba 2 M(SeO 3 ) 2 Cl 2 (M = Cu 2+ , Ni 2+ , Co 2+ , Mn 2+ ) and Pb 2 Cu(SeO 3 ) 2 Cl 2 with Tunable Spin S : Syntheses and Characterizations.

A series of analogous chain selenite chlorides Ba 2 M(SeO 3 ) 2 Cl 2 (M = Cu 1 , Ni 2 , Co 3 , Mn 4 ) and Pb 2 Cu(SeO 3 ) 2 Cl 2 5 with tunable spin S from S = 1/2 to S = 5/2 have been hydrothermally synthesized and characterized. These analogues crystallized in the orthorhombic Pnnm space group (monoclinic P 2 1 / n space group for 5 ) all containing M 2+ -SeO 3 -M 2+ spin chains, which are further separated by the Ba 2+ ions (Pb 2+ for 5 ). The magnetic susceptibility results of 1 , 2 , and 5 show broad maxima around 80.0, 18.9, and 78.0 K, respectively, indicating good one-dimensional (1D) magnetism. Meanwhile, no long-range order (LRO) is observed down to 2 K for both 1 and 5 , while the isostructural compounds 2 , 3 , and 4 exhibit LRO at 3.4 K, 10.8 K, and 5.7 K, respectively, which are further confirmed by the heat capacity and electron spin resonance results, as well as the observed spin-flop transitions in the M - H curves measured at 2 K below T N . The magnetizations of 1 - 5 at 7 T are still far from saturation. In addition, thermal stability and FT-IR and UV-vis-NIR spectroscopy of 1 - 5 are reported.