Answer:
Pentasulfur nonanitride.
Explanation:
In order to name a compound properly, we need to identify the type of a compound we have. The given compound consists of two non-metals, sulfur and nitrogen. This implies that we have a covalent compound in contrast to an ionic compound which consists of a metal and a non-metal.
To name a molecular/covalent compound, we should use prefixes stating the number of atoms we have. In this case, we have 5 sulfur atoms. The prefix for 5 is 'penta'. That said, we have 'pentasulfur' as our beginning of the name.
We also have 9 nitrogen atoms. The second atom in the molecular formula would have an ending of '-ide', so we expect to have 'nitride'. Adding a prefix for 9, we'd have 'nonanitride'.
Putting everything together, the name is pentasulfur nonanitride.
Some common prefixes:
mono – one (we don't state mono for the first atom, e. g., we would name CO as carbon monoxide instead of monocarbon monoxide);
di – two;
tri – three;
tetra – four;
penta – five;
hexa – six;
hepta – seven;
octa – eight;
nona – nine;
deca – ten.
Notice that 'decanitride' would be correct in case you had 10 nitrogen atoms, similarly, tetra and hexa stand for 4 and 6 instead of 5 given sulfur atoms.