Ammonium Hydrogen Fluoride
Help with writing formulas for compounds??
2. Sodium Chloride.
3. Carbon Tetrachloirde
4. Magnesium Bromide
5. Aluminum Iodide
6. Hydrogen Hydroxide
7. Iron (II) fluoride
8. Carbon Dioxide
9. Sodium Carbonate
10. Ammonium Sulfide
11. Iron (II) Oxide
12. Magnesium Sulfate
13. Sodium Phosphate
14. Dinitrogen Pentoxide
15. Phosphorus trichloride
16. aluminum sulfite
17. copper (I) carbonate
18. Potassium Hydrogen Carbonate
19. Sulfur Trioxide
I have A LOT more of them to do, but doing these examples will help, and help me study for this huge test I have tomorrow on this stuff. Thankss so much!!!
OMG! Thank you sooo much, all of you. You have no idea how greatful I am for this!!! 
2. NaCl
3. CCl4
4. MgBr2
5. AlI3
6. HOH
7. FeF2
8. CO2
9. Na2CO3
10. (NH4)2S
11. FeO
12. MgSO4
13. Na3PO4
14. N2O5
15. PCl3
16. (Al)2(SO3)3
17. Cu2CO3
18. KHCO3
19. SO3
I had trouble w/ these when I was first learning them, I suggest making flashcards for all the polyatomic ions