Molar mass of vitamin B1, C12H17N4OS = 265.34 g/ mol
Molar mass of vitamin B2, C17H20N4O6 = 376.37 g/ mol
Molar mass of vitamin B5, C9H17NO5 = 219.24 g/ mol
Molar mass of vitamin B6, C8H11NO3 = 169.18 g/ mol
Molar mass of vitamin B7, C10H16N2O3S = 244.31 g/ mol
Now,
Order of increasing molar mass = B6 < B5 < B7 < B1 < B2
I believe each oxygen shares 2 elections with the other.
