(infinity)1[Ho2Cl6{1,3-Ph(CN)(2)}(3)] - A variant of the PaCl5 structure condensed to double strands in a rare earth benzodinitrile coordination polymer

Single crystalline transparent pink(infinity)(1)[Ho2Cl6{1,3-Ph(CN)(2)}(3)] (1,3-Ph(CN)2 = 1,3-benzodinitrile, C6H4(CN)(2)) was obtained by the reaction of anhydrous holmium trichloride with a melt of 1,3-benzodinitrile at 175 degrees C. The trichloride structure is broken up by the dinitrile ligands and re-arranged to double strands of edge connected pentagonal bipyramids of chlorine and nitrogen atoms. The structure can be deduced from the PaCl5 structure type by condensation of two PaCl5 strands and exchange of two chlorine atoms with nitrile groups. The double strands exhibit ligand free cavities of 600-800 pm diameter.