Q57. Among $\mathrm { CrO } , \mathrm { Cr } _ { 2 } \mathrm { O } _ { 3 }$ and $\mathrm { CrO } _ { 3 }$, the sum of spin-only magnetic moment values of basic and amphoteric oxides is $\_\_\_\_$ $10 ^ { - 2 } \mathrm { BM }$ (nearest integer). (Given atomic number of Cr is 24 )