Polyatomic Ions

Bi- (or you read "hydrogen" in the name)

A polyatomic ion where a *H⁺ ion is added*. Add the H to the front of the formula and add one to the charge. Carbonate is CO₃²⁻ → *Bi*carbonate (also known as hydrogen carbonate) is *H*CO₃*⁻*

Thio-

A polyatomic ion where a *sulfur replaces an oxygen* if present. If there isn't an oxygen, then simply add the sulfur. Charge doesn't change. Sulfate is SO₄²⁻ → *Thio*sulfate is S*₂*O*₃*²⁻ Cyanate is CN⁻ → *Thio*cyanate is SCN⁻

-ate

A polyatomic ion where a certain number of *oxygens* are bonded to the atom. Sulf*ate* = SO₄²⁻ Nitr*ate* = NO₃⁻ Phosph*ate* = PO₄³⁻

-ite

A polyatomic ion with *one LESS oxygen than the "-ate"* of that element. Charge is the same as the "-ate". Nitrate is NO₃⁻ → Nitr*ite* is NO*₂*⁻ Sulfate is SO₄²⁻ → Sulf*ite* is SO*₃*²⁻

Hypo-

A polyatomic ion with *one LESS oxygen than the "-ite"* of that element. Charge is the same as the "-ate". Nitrite is NO₂⁻ → *Hypo*nitrite is NO⁻ Sulfite is SO₃²⁻ → *Hypo*sulfite is SO*₂*²⁻

Per-

A polyatomic ion with *one MORE oxygen than the "-ate"* of that element. Charge is the same as the "-ate". Chlorate is ClO₃⁻ → *Per*chlorate is ClO*₄*⁻ Iodate is IO₃⁻ → *Per*iodate is IO*₄*⁻

Polyatomic ion

An ion composed of multiple elements. Remember these are compounds that have an overall net charge. Ex: SCN⁻, OH⁻, PO₃³⁻, etc.

Tartrate

C₄H₄O₆²⁻

Benzoate

C₆H₅COO⁻

Citrate

C₆H₅O₇³⁻

Formate

HCOO⁻ or HCO₂⁻

Hypoiodite

IO⁻

Periodate

IO₄⁻

Acetate

Note: Acetate may also be represented as C₂H₃O₂⁻

Dichromate

Note: Di- here does NOT translate into two chromates.

Permanganate

Note: Per- here does NOT mean plus one oxygen as usual. Rather, it means plus one on the net charge.

Peroxide

Note: Per- here means add an oxygen to oxide.

Tellurate

TeO₄²⁻

Tungstate

WO₄²⁻