A nano-crystalline Prussian blue like room-temperature molecule- based magnet K~0~.~4~5V~1~.~1~2^ⅡV~0~.~1~9^Ⅲ [Cr(CN)~6](SO~4)~0~. ~1~3·4.34H~2O was synthesized by slow reaction of VSO~4·2.5H~2O and K~3[Cr(CN)~6]·2.5H~2O in aqueous solution under anaerobic conditions. Its XRD pattern can be indexed to face-centered cubic (fcc) unit cell with a=1.178 nm. The widths of the diffraction peaks show that the average size is 5 nm. The magnetic ordering temperature (T~C) of the magnet is 340 k, the coercive filed H~C keeps 5～6 Oe in the range of 40～310 K, and increases to 120 Oe at 1.83 K. It is relative stable to air convinced by the second magnetic measurement results (T~C=340 k, H~C=146 Oe at 5 K) after the sample was stood in air for 10 days. Compared with the reported high T~C V－Cr－CN magnets, the remarkable observation is that the long range ferrimagnetic ordering and spin glass behavior are coexistence in the system, the latter was confirmed by frequency dependent AC magnetic susceptibility.

Key words: NANOPHASE MATERIALS, MAGNET, VANADIUM COMPLEX, CHROMIUM COMPLEX, MAGNETISM, X-RAY DIFFRACTION ANALYSIS, MAGNETIZATION