[vicereine]

I have 4 polyatomic ions that I have to name, I didn't have a problem until I went to check my answers online. Two showed up in my search fine, but the other two come up slightly different. I'm pretty sure they are right given the example questions I did earlier (that had the answers to check in the back of the book), specifically Pb(ClO3)2 = lead(II) chlorate.

so just want to check if these are right:

Ba3(PO4)2 = barium(II) phosphate

Hg(ClO3)2 = mercury(II) chlorate

[AWK]

Try phosphate(V)

Chlorate(V)
[chlorate(VII)  ClO₄^- also exists]

[Astrokel]

You can also name Hg2+ as mercuric 

[vicereine]

There's a mercuric chloride but chlorate doesn't really come up.

[AWK]

Both mercuric chlorates Hg(ClO3)2 and Hg(ClO4)2 exist though they are can easily explode

[sjb]

Try phosphate(V)

Chlorate(V)
[chlorate(VII)  ClO₄^- also exists]

Looking at the style of nomenclature used, isn't ClO₄^- likely to be perchlorate, c.f. NaIO₄ - sodium periodate?

It's possible that PO₄^3- is phosphate, and PO₃^3- phosphite in this instance too.

Not that I disagree with you, semisystematic nomenclature can be annoying sometimes...

S