Storage of Sodium & Phosphorus

Sodium

Science ASSIST recommends that sodium metal is:

• stored under paraffin oil as a storage solution as it is a non-flammable liquid. The use of kerosene, whilst suitable, introduces additional hazards due to it being an aspiration hazard as well as being a flammable liquid. Kerosene also has a much lower boiling point than paraffin, and is more prone to loss of liquid by evaporation.
• stored in a wide mouthed clear glass screw capped jar. The clear glass enables the level of the paraffin solution to be easily seen. The wide mouth enables easy access to obtain the sodium.
• the glass jar could be stored in a secondary containment such as a chemically resistant plastic container. E.g. a polypropylene beaker would be suitable
• purchased in small quantities as required

The use of a sand bath is not considered necessary for storage of sodium. It could mask the loss of storage fluid. For safe handling procedures see SOP: Demonstrating the reaction of alkali metals lithium and sodium with water

Phosphorus

Phosphorus is not on our list of recommended chemicals because of the significant risks associated with its storage and use. This includes the following:

• Fire hazard: White phosphorus is a severe fire hazard and will ignite on exposure to air. It is classified as DG 4.2 and packing group I, which represents 'high danger'. It is a pyrophoric solid, spontaneously combustible in air, which is why it should be stored under water at all times
• Toxic hazard: Upon combustion in air both red and white phosphorus produce highly toxic phosphorus pentoxide. In water with low oxygen content may produce phosphine. Therefore inhaling the fumes should be avoided at all times.
• Security hazard: Phosphorus is listed as a chemical of security concern and a drug precursor, category 1. see: https://www.nationalsecurity.gov.au/chemical-security-subsite/Files/code... and Code of Practice for Supply Diversion into Illicit Drug Manufacture.

Science ASSIST strongly recommends the disposal of phosphorus by a licenced chemical disposal contractor. See our list of School science suppliers for contact details.

If your school decides to keep phosphorus we recommend that a site specific risk assessment be conducted concerning its storage, handling and emergency response procedures.

White Phosphorus:

• should always be stored under water in a clear glass jar (Note: many schools may have traditionally kept the glass jar in a tin in a sand bath)
• In cold locations, ensure that it is stored appropriately to prevent the water from freezing which might cause the jar to break
• Containers should be regularly monitored and the phosphorus should not be allowed to dry out
• Should always be stored in a secure chemical store away from incompatible substances
• Should be handled under water in an operating fume cupboard, with appropriate PPE and established handling safe procedures.

Red phosphorous is more easily managed and less hazardous than white phosphorus. It should be stored with other flammable solids away from oxidising agents, alkalis and other incompatible chemicals.

References

Agency for Toxic Substances and Disease Registry. Public Health Statement White Phosphorus CAS#: 7723-14-0 https://www.atsdr.cdc.gov/phs/phs.asp?id=286&tid=52 (Last accessed: December 2016)

CLEAPSS. Phosphorus: (Hazcard 73A) http://science.cleapss.org.uk/Resource-Info/HC073A-Phosphorus-P-white-ye... (updated March 2017) (login required)

CLEAPSS. Sodium. (Hazcard CLP88) http://science.cleapss.org.uk/Resource-Info/HC088-Sodium.aspx (updated March 2017) (login required)

‘How should I store reactive metals like sodium, potassium, lithium, etc?’ On Flinn scientific website's FAQ: https://www.flinnsci.com/safety-faq/faq2006/ (updated January 2017)

'Kerosene', Safety Data Sheet, Chem-Supply website, https://www.chemsupply.com.au/documents/KT0021CHOO.pdf (August 2013)

‘Phosphorous, red’ Safety Data Sheet, Please refer to the Sigma-Aldrich website for the latest version. https://www.sigmaaldrich.com.

‘Sodium metal’, Safety Data heet, Chem-Supply website, https://www.chemsupply.com.au/documents/SL0741CH6J.pdf (May 2013)

Standard Australia. 2012. AS/NZS 5026:2012 (Incorporating Amendment No. 1): The storage and handling of Class 4 dangerous goods. Sydney, Australia.

'White phosphorus incident management' Public Health England website. https://www.gov.uk/government/uploads/system/uploads/attachment_data/fil... (January 2016)