Iron(II) sulfide (CAS 1317-37-9): storage and disposal

Black iron(II) sulfide sticks turn up in school, college and university prep rooms as legacy stock, bought years ago for hydrogen sulfide demonstrations and then forgotten. The solid itself is not classified as hazardous on the sources we checked, but what it gives off with acid is a different matter, and that decides how it is shelved, described and collected.

CAS number: 1317-37-9
Form: Solid
Storage class: General
Usual EWC code: 16 05 09

What to do this week

Check the label is readable and write down the opened date if it is not already there.
Check it is stored as general stock and apart from the items listed under "Do not store with".
If you no longer need it, add it to your disposal list so it goes on the next collection.

Safe storage in a school or lab

Acids are the thing to keep clear of. Hydrochloric, sulfuric, nitric and every other acid in the prep room can set this solid off, because sulfides release toxic hydrogen sulfide gas when an acid reaches them. A spilt acid bottle on a shared shelf is the realistic way that happens. Give the sticks their own labelled container on a different shelf from the acid store, ideally in a separate cupboard, and keep the lid tight so room air does not reach them. A container that has stood in a humid store or beneath a leaking tap should have its condition reported before collection. Date the container on arrival and note the stock quantity in the record so unused sticks do not sit for decades unseen.

How to tell it has deteriorated

Look first for the colour of the sticks. Fresh black material that has stood in air tends to develop rusty brown patches as the surface oxidises, and any rotten-egg smell around the container should be reported as a possible indication of hydrogen sulfide, without opening the container to investigate. Damp or clumped sticks, loose crumbs at the bottom of the jar and rust staining on the cap or the shelf below are all signs that the stock has been taking in water. A container that is unexpectedly warm should be left undisturbed and reported for specialist assessment. This substance does not have a long list of dramatic changes, so an undated jar of legacy sticks is judged on its condition and the state of the label rather than any single clear marker.

How it must be disposed of

By specialist collection only. It never goes down the drain or into general waste. It is normally packed in a non-regulated or low hazard laboratory pack with compatible chemicals.

Leftover sticks are packed into a compatible group away from any acid, because the risk in the lab pack is the same one as on the shelf. The material is not classified as hazardous on the sources we checked, but it remains a chemical waste and has to be described accurately, so say plainly that these are iron(II) sulfide sticks and note if any are damp, crumbled or rusty. A waste transfer note travels with the movement. Nobody should wash the sticks away, put them in the bin or try to react them off with acid in the prep room, since that is exactly how hydrogen sulfide gets made indoors. Leave them in the original container if it is sound, labelled, and book a specialist collection.

Waste codes and transport details for Iron(II) sulfide
EWC code, laboratory chemicals	16 05 09
Hazardous waste	No

The code depends on where the waste came from and what it is mixed with. Use the waste code finder to see why.

Do not store with

Named chemicals to keep apart

Hydrobromic acidSulfides release toxic hydrogen sulfide gas with acids.
Hydrochloric acidSulfides release toxic hydrogen sulfide gas with acids.
Hydroiodic acidSulfides release toxic hydrogen sulfide gas with acids.
Nitric acidSulfides release toxic hydrogen sulfide gas with acids.
Perchloric acidSulfides release toxic hydrogen sulfide gas with acids.
Phosphoric acidSulfides release toxic hydrogen sulfide gas with acids.
Sulfuric acidSulfides release toxic hydrogen sulfide gas with acids.
Trichloroacetic acidSulfides release toxic hydrogen sulfide gas with acids.

Common quantities we collect

Usually held as: sticks, legacy stock.

Part-used bottles and full containers are both fine. Tell us the size and how many, and an estimate is enough for a first price.

Where it is commonly held

Questions

Can old iron(II) sulfide sticks go out with the ordinary rubbish?

No. Even though the solid is not classified as hazardous on the sources we checked, it is still a chemical waste and has to be described accurately. Contact with acid makes hydrogen sulfide, so it goes by specialist collection and never into a bin or a sink.

Why does the jar smell of bad eggs when it is sealed?

A rotten-egg smell may indicate hydrogen sulfide, which can be generated when iron(II) sulfide contacts acid. Do not open the container to investigate. Leave it undisturbed and report the suspected gas release for specialist assessment. Move nothing else near it, keep acids away and arrange collection.

Is it a problem if the sticks have gone rusty brown?

It tells you the surface has oxidised in air and the container has not been sealed well. The stock is still a waste that needs specialist collection. Record the colour change and any damp crumbs on the container description.

Where in a prep room should these sticks sit?

On a dry shelf in a sealed, labelled container, in a different cupboard from every acid. A shared shelf under the acid store is the wrong place, because one leaking bottle can reach them.