Use of "That of" and "That in" in sentences

English as a Second Language English Vocabulary, Grammar and Idioms
1

I have seen that “That of” and “that in” are used in sentences comparing two things. For example,

The country has abundant sources of natural resources than that of its neighbors.

Please help me understand the formation of these types of sentences.

2

The sentence you quote is incorrect.

In a sentence such as
Their land is richer than that of their neighbours
this is a more concise way of saying
Their land is richer than the land belonging to their neighbours.

3

Thank You.

Please help me to understand other two forms, That in and That to,

Like “That of” is used to state belonging or possession as you mentioned that land belonging to the neighbor. Similarly, when to use “That in” and “That to”.

Thanks in advance.

4

That of’ is not used for belonging. It is used for comparison - comparing one thing to another.
The other phrases are also used for comparison. The only difference is the preposition which is necessary within the context as a whole:

The temperature in Orlando is generally higher than that in Buffalo.
The temperature in Orlando is generally higher than the temperature is in Buffalo.

The building to the East of us is taller than that to the West.
The building to the East of us is taller than the building to the West of us.