# What is the formula of potassium ammonium sulfate?

I tried to get the formula of potassium ammonium sulfate. What I got is $\ce{K(NH4)2SO4}$ but I don't think this the right formula. I searched on the internet and found an answer ($\ce{KNH4SO4}$), but I don't think it is correct.

So what is the correct formula of potassium ammonium sulfate?

• It would help if you explained your logic for why you think $\ce{K(NH4)SO4}$ is incorrect and why $\ce{K(NH4)2SO4}$ should be the answer. – Nicolau Saker Neto Jun 20 '14 at 16:17
• your answer doesn't have zero net charge $+1(\ce K)+2(\ce{(NH4)2})-2(\ce{SO4})=1\ne0$ but $+1(\ce K)+1(\ce{NH4})-2(\ce{SO4})=0$ – RE60K Jun 20 '14 at 16:38
• oh yes ! you are right ! I didn't pay attention for the net charge – Maher Jun 20 '14 at 17:27

$\ce{K(NH_4)SO_4}$ is the correct formula. You have two unipositive cations and a single dinegative anion. The total charge must be zero.