Phosphorus pentachloride (CAS 10026-13-8): storage and disposal
Phosphorus pentachloride is a pale, crystalline solid familiar from sixth form and college chemistry stores, where it was long kept for testing for hydroxyl groups, and it also appears in university stock. It reacts violently with water, releasing hydrogen chloride, and it fumes and corrodes metal. It is fatal if inhaled and causes severe burns. An old bottle may well be damaged by slow contact with damp air, so its seal decides what happens next.
- CAS number
- 10026-13-8
- Form
- Solid
- Storage class
- Toxic
- Signal word
- Danger
- Usual EWC code, laboratory stock
- 16 05 06*
Corrosive
Acute toxicity
Serious health hazard
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
Most stock comes as a small glass bottle of pale crystalline solid, and in an old store the first thing you notice is often the state of the cap. Moist air reaches the solid every time the bottle is opened, so a crust builds on the neck and metal fittings close by start to corrode. The bottle belongs in a dry, locked and ventilated store with a stock record, on a resistant tray, away from food and drink, oxidisers and acids. Keep all water based stock away from it, including ammonia solution, formalin, hydrochloric acid, hydrogen peroxide, sodium hydroxide and sodium hypochlorite. A prep room shelf directly above a wet bench is the common mistake, as a single drip can start a violent reaction.
How to tell it has deteriorated
Good stock is a pale yellow to off-white crystalline solid, reasonably free flowing. What does not fit is a wet looking or pasty mass, because moist air breaks it down to acidic liquids, and these often gather below the crystals or at the neck. A sticky crust around the cap, fumes seen inside the bottle and a sharp acid smell in the cupboard all mean the seal has failed. Corroded metal on or near the bottle is a further sign, and paper labels often go brown or lift. Pressure may build in an old sealed bottle as hydrogen chloride forms. Do not open or loosen a bottle in this condition. Leave it upright on its tray and report it as damaged stock.
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.
Packing is the awkward part, since a water reactive solid that fumes cannot sit with aqueous stock in a lab pack and a corroded closure may not survive much handling. Describe the bottle honestly: the name, approximate amount, closure type and whether the contents look dry, pasty or wet. That description decides how it is grouped and whether it needs extra protection on the way out. In most schools and colleges the code is 16 05 06*. Its only route off site is a specialist collection. Do not try to use it up, and never add water or any other substance to treat it. It must not go into a sink, a drain, a general waste bin or a skip at any stage.
| 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.
- Ammonia solutionReacts with water, releasing heat and often a flammable or corrosive gas, so keep it away from all water based stock.
- Calcium hypochloriteToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
- FormalinReacts with water, releasing heat and often a flammable or corrosive gas, so keep it away from all water based stock.
- Hydrochloric acidReacts with water, releasing heat and often a flammable or corrosive gas, so keep it away from all water based stock.
- Hydrogen peroxideReacts with water, releasing heat and often a flammable or corrosive gas, so keep it away from all water based stock.
- 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.
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- Potassium permanganateToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
- Sodium hydroxideReacts with water, releasing heat and often a flammable or corrosive gas, so keep it away from all water based stock.
- Sodium hypochloriteReacts with water, releasing heat and often a flammable or corrosive gas, so keep it away from all water based stock.
- Sulfuric acidToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
Common quantities
Usually held as: solid.
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.
- H312 Harmful in contact with skin.
- H314 Causes severe skin burns and eye damage.
- H330 Fatal if inhaled.
- H373 May cause damage to organs through prolonged or repeated exposure.
- EUH014 Reacts violently with water.
- EUH029 Contact with water liberates toxic gas.
Precautionary statements
- P260 Do not breathe 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.
- 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.
- P301+P330+P331 IF SWALLOWED: Rinse mouth. Do NOT induce vomiting.
- P302+P361+P354 IF ON SKIN: Take off immediately all contaminated clothing. Immediately rinse with water for several minutes.
- P304+P340 IF INHALED: Remove person to fresh air and keep comfortable for breathing.
- P305+P354+P338 IF IN EYES: Immediately rinse with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
- P316 Get emergency medical help immediately.
- P319 Get medical help if you feel unwell.
- P320 Specific treatment is urgent (see supplemental first aid instruction on this label).
- P321 Specific treatment (see supplemental first aid instruction on this label).
- P330 Rinse mouth.
- P363 Wash contaminated clothing before reuse.
- P403+P233 Store in a well-ventilated place. Keep container tightly closed.
- P405 Store locked up.
- P501 Dispose of contents and container in accordance with local, regional, national and international regulations.
- P301+P316 IF SWALLOWED: Get emergency medical help immediately.
- P302+P352 IF ON SKIN: Wash with plenty of water.
- P317 Get medical help.
- P362+P364 Take off contaminated clothing. And wash it before reuse.
Substance as classified, dilutions may differ.
Questions
It is still in date for our hydroxyl test. Why would we clear it?
Age is not the only issue. Each opening lets in moist air, and the solid slowly breaks down. If the bottle has crusted, turned pasty or is hard to open, it should leave. A cleaner bottle kept in use still needs a dry locked store and a current record.
The solid has become wet and sticky. Is it safe to move?
Treat it as damaged. Pressure may have built up from hydrogen chloride, and a corroded cap may fail. Do not open it or carry it around the building. Keep it upright where it is, keep water away and ask for advice when arranging collection.
Can it go with our other chlorides on the salts shelf?
No. Unlike ordinary metal chlorides, it reacts violently with water and is fatal if inhaled, so it needs its own dry place in a locked ventilated store. The salts shelf also tends to hold damp sensitive and water based stock nearby, which is the wrong company.
