A group of new selenite-chlorides of strontium and d-metals (Co,Ni): Synthesis, thermal behavior and crystal chemistry

The new selenite-chlorides with composition Sr3(SeO3)2Cl2 (I) and Sr2M(SeO3)2Cl2 (M=Co, Ni (II and III)) were obtained. They crystallize in monoclinic system I: space group C2/m, a=13.203(2) A, b=5.5355(8) A, c=6.6170(10) A, β=95.89(1)o, Z=2; II Space group P21/n, a=5.3400(10) A, b =6.4279(6) A, c=12.322(1) A, β=92.44(1)o, Z=2; III: space group P21/n, a=5.3254(11) A, b=6.4363(13) A, c=12.197(2), β=92.53(3)o, Z=2. All three compounds are constructed in the same manner. Sr polyhedra form infinite layers, which are interconnected into a 3D framework by means of Sr polyhedra in the case of I or Co and Ni polyhedra in the case of II and III. Se atoms are situated inside the channels of the 3D framework. The topological analysis of ELF for I confirmed that the lone electron pairs of SeO3 groups are located inside these channels. - Graphical abstract: Three new selenite-chlorides Sr3(SeO3)2Cl2 and Sr2M(SeO3)2Cl2 (M= Co,Ni)