and the primitive cell was defined by Mn9Cr4 ions as showed in Figure . As this structural motif of 1 propagate in one crystal direction, the supercell was set as 1 x 10 x 1. The number of warm-up steps and Monte Carlo sampling steps were set to 500 000, and the magnetic susceptibility was calculated in 2-300 K temperature range with 2 K step. The results are depicted in Figure and the temperature profile of T nicely reproduces the main features of experimental magnetic data of 1 and explains that despite antiferromagnetic exchange, the spin topology produces large magnetic moments of these 1D ladder-like chains.