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Chemistry Forums for Students => Inorganic Chemistry Forum => Topic started by: xshadow on September 30, 2020, 08:17:23 AM

Title: hard-soft SO4 2- and SO3 2-
Post by: xshadow on September 30, 2020, 08:17:23 AM
Hi

I don't understand why SO42- is  considered a hard base while So32- is a soft (borderline) one


For monoatomic ionic species like Mg2+ vs K+ (or Ba2+)  is say that Mg2+ is hard because has a much higher  charge/ionic radius of the metal ion than Ba2+ or K+


But for polyatomic ions like SO42- or SO32- how can i say this?
what  parameter I have to consider to say that SO42- is hard while SO32- is a borderline base?

The negative charge is in both case 2-
THe ionic radius ...of the entire ion I think is not so much different...

thanks