sentence: Manganese compounds can be black, brown, pink, red, green, blue, and purple.
sentences_before: Manganese is a silvery-gray metal and is part of the group known as the transition metals. It is similar to iron. It is hard to melt, but easy to oxidize.
sentences_after: They are unreactive. They are normally black in colour.
concept_name: manganese compound
headings: Manganese Properties
categories: Chemical elements Metals