Hey there!
Cr₄(P₂O₇)₃
Cr: 4 x 51.996 = 207.984
P: 6 x 30.97 = 185.82
O: 21 x 16 = 336
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729.804 g/mol
The molar mass of Cr₄(P₂O₇)₃ is 729.804 g/mol.
Hope this helps!
