Nickel(II) sulfate (CAS 7786-81-4): storage and disposal
Green nickel(II) sulfate hexahydrate has been a staple of electroplating and crystal-growing demonstrations in school, college and university stores. It carries a long list of classifications: may cause cancer by inhalation, a respiratory and skin sensitiser, suspected genetic damage, may damage the unborn child, organ damage through repeated exposure and very toxic effects on aquatic life. The dust is the part that matters most.
- CAS number
- 7786-81-4
- Form
- Solid
- Storage class
- Toxic
- Signal word
- Danger
- Usual EWC code, laboratory stock
- 16 05 06*
Harmful or irritant
Serious health hazard
Hazardous to the environment
What to do this week
- Without moving anything that looks damaged, check the label is readable and write down the opened date if it is not already there.
- Check it is stored as toxic stock, and apart from anything listed under "Do not store with" on this page. If nothing is listed, that does not prove it is safe with everything.
- If you no longer need it, add it to your disposal list so it can be included in a collection.
Safe storage in a school or lab
Anything that raises dust is the problem, so start with the lid. Keep the jar tightly closed in a locked toxic-stock cupboard with a stock record, in a tray so that spilt green crystals do not spread across the shelf. Keep nickel sulfate in its locked toxic-stock cupboard, segregated from chemicals identified as incompatible in its safety data sheet. In a school prep room it often sits beside copper sulfate, and the two are easily confused by colour, so label it by its full name and form. Dedicated spatulas avoid cross-contamination. A student should never be handed the jar directly.
How to tell it has deteriorated
Healthy crystals are a clear, even green. A hexahydrate stored in warm, dry conditions can lose some of its water and develop a paler, powdery surface, while one stored in damp air can clump and cake. Either change tells you the jar has not been kept sealed. Green crust on the thread, staining on the shelf and a label that has gone soft or faded are the practical warning signs, along with powder dust on the outside of the jar. Beyond these changes, the salt gives few dramatic signs of age. A jar whose contents cannot be confirmed from the label should be reported.
How it is disposed of
We arrange this by specialist collection. We do not publish a drain or general waste route for any chemical. It is normally packed in a toxic laboratory pack with compatible chemicals.
What must not be done is any dust-raising tidy-up. Do not sweep up spilt crystals dry, wash them into a sink or put them in the bin, because the cancer-by-inhalation and aquatic classifications follow the material everywhere. Keep it upright with the lid on, and mention any crystals on the outside of the jar. The usual code, which the producer confirms when classifying the waste, is 16 05 06* in a laboratory pack and 16 05 07* for discarded inorganic stock outside one. Describe solid and any plating solution separately with volumes, and request a specialist collection.
| Usual EWC code, laboratory stock | 16 05 06* |
|---|---|
| Discarded inorganic chemical, not a laboratory pack | 16 05 07* |
| Usually classed as hazardous waste | Yes |
The code depends on where the waste came from and what it contains, and classifying it is the producer's duty. Use the waste code finder to see why.
Do not store with
- OxidiserToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
- AcidToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
Named chemicals to keep apart
- Acetic acidToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
- Calcium hypochloriteToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
- Hydrochloric acidToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
- Hydrogen peroxideToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
- Nitric acidToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
- Potassium nitrateToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
- Potassium permanganateToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
- Sulfuric acidToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
Common quantities
Usually held as: hexahydrate.
Tell us the container size and how many you hold. An estimate is enough to start with, and some items cannot be priced until someone has looked at them.
Where it is commonly held
Hazard statements
- H302 Harmful if swallowed.
- H315 Causes skin irritation.
- H317 May cause an allergic skin reaction.
- H332 Harmful if inhaled.
- H334 May cause allergy or asthma symptoms or breathing difficulties if inhaled.
- H341 Suspected of causing genetic defects.
- H350i May cause cancer by inhalation.
- H360D May damage the unborn child.
- H372 Causes damage to organs through prolonged or repeated exposure.
- H410 Very toxic to aquatic life with long lasting effects.
Precautionary statements
- P203 Obtain, read and follow all safety instructions before use.
- P233 Keep container tightly closed.
- P260 Do not breathe dust, fume, gas, mist, vapours or spray.
- P261 Avoid breathing dust, fume, gas, mist, vapours or spray.
- P264 Wash hands and exposed skin thoroughly after handling.
- P270 Do not eat, drink or smoke when using this product.
- P271 Use only outdoors or in a well-ventilated area.
- P272 Contaminated work clothing should not be allowed out of the workplace.
- P273 Avoid release to the environment.
- P280 Wear protective gloves, protective clothing, eye protection and face protection.
- P284 In case of inadequate ventilation wear respiratory protection.
- P301+P317 IF SWALLOWED: Get medical help.
- P302+P352 IF ON SKIN: Wash with plenty of water.
- P304+P340 IF INHALED: Remove person to fresh air and keep comfortable for breathing.
- P317 Get medical help.
- P318 If exposed or concerned, get medical advice.
- P319 Get medical help if you feel unwell.
- P321 Specific treatment (see supplemental first aid instruction on this label).
- P330 Rinse mouth.
- P332+P317 If skin irritation occurs: Get medical help.
- P333+P317 If skin irritation or rash occurs: Get medical help.
- P342+P316 If experiencing respiratory symptoms: Get emergency medical help immediately.
- P362+P364 Take off contaminated clothing. And wash it before reuse.
- P391 Collect spillage.
- P403 Store in a well-ventilated place.
- P405 Store locked up.
- P501 Dispose of contents and container in accordance with local, regional, national and international regulations.
Substance as classified, dilutions may differ.
Questions
Why is nickel sulfate such a concern when it looks like ordinary green crystals?
It is classified as able to cause cancer by inhalation, as a sensitiser, as suspected of causing genetic defects, as able to damage the unborn child and as very toxic to aquatic life. Dust is the main route.
What should happen to leftover plating or crystal-growing solution?
It must never be poured away. It is very toxic to aquatic life. Collect it in a labelled bottle with a volume, describe it separately from the solid and include it in the collection request.
Why has the surface of the crystals turned pale?
Hexahydrate can lose some water in warm, dry storage, leaving a paler powdery coat. It is a sign of poor sealing. Record it and keep the jar closed and upright.
Can we keep it next to copper sulfate?
The two salts can look similar and may be mistaken for one another. Nickel sulfate belongs in a locked toxic-stock cupboard with a stock record and a clear label stating its full name. Follow the safety data sheets and the store's compatibility arrangements when deciding whether they can be kept alongside one another.
