5 Steps to a 5 AP Chemistry 2019

Common Ions ❮ 381

Ligand Formula (abbreviation) Ligand name

Cyanide ion CN- cyano

Fluoride ion F- fluoro

Hydride ion H- hydrido

Hydroxide ion OH- hydroxo

Iodide ion I- iodo

Nitrite ion NO 2 - nitrito

Oxalate ion C 2 O 42 - oxalato

Sulfide ion S^2 - thio

Thiocyanate ion SCN- thiocyanato

Ammonia NH 3 ammine

Ethylenediamine en ethylenediamine

Water H 2 O aqua

Colors of Common Ions in Aqueous Solution

Most common ions are colorless in solution; however, some have distinctive colors. These

colors have appeared in questions on the AP exam.

Fe^2 + and Fe^3 + various colors

Cu^2 + blue to green

Cr^2 + blue

Cr^3 + green or violet

Mn^2 + faint pink

Ni^2 + green

Co^2 + pink

MnO 4 - dark purple

CrO 42 - yellow

Cr 2 O 72 - orange

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