Question

What is the name of `As_4S_10`?

Answer 1

Tetra-arsenic deka-sulfide. It is also wrongly called arsenic penta-sulfide, which would be `As_2O_5`

Explanation:

In non-salt dual element compounds, we use greek numerals to denote te number of atoms of each kind.
First element is usually called by its name, and the other with the suffix -ide.
Tetra- and deka- are the count-prefixes for 4 and 10.