There are two sentences in inorganic chemistry of Wuhan University, which are copied as follows:

1, located between IIA and IB, Ⅲ b Ⅳ b Ⅳ bb, is called transition family, and its elements are called transition elements.

2. Hydrates of transition element oxides are alkaline at low prices and acidic at high prices.

So we have

1, Mn is in group ⅶ B, and Mn is a transition element.

2. Manganese oxide hydrate is alkaline at low price and acidic at high price.

3. The hydrate of oxide is hydroxide.

4. Manganese hydroxide is alkaline at low price and acidic at high price.

Proposition 4 can be expressed as follows:

Mn shows covalent bond +2 valence-low valence, and hydroxide shows alkalinity, that is,

H——O——Mn——O——H →( H——O—)+—Mn—+(—O——H)

So H-O-Mn-O-H is written as Mn(OH)2.

Mn shows covalent bond +7 valence-high valence, and hydroxide shows acidity, that is,

H——O——Mn——3O→H——+(—O——Mn——3O)，

So h-o-Mn-3o is written as HMnO4.