English Safety Data Sheet Database 中文版 MSDS

cesium

CAS No. 7440-46-2 | PubChem CID 5354618
Section 1. Identification
Chemical Namecesium CAS No.7440-46-2
Synonyms Chinese Name
Molecular FormulaCs Molecular Weight132.91
UN No.1407 Data SourcePubChem (NIH/NLM)
GHS Hazard Classification
Signal Word DANGER
Pictograms GHS02 · Flammable GHS05 · Corrosive
Hazard Statements H260H314H318
Precautionary Statements P223P231+P232P260P264P264+P265P280P301+P330+P331P302+P335+P334P302+P361+P354P304+P340P305+P354+P338P316P317P321P363P370+P378P402+P404P405P501

Section 2. Hazards Identification

This chemical does not meet GHS hazard criteria for 0.6% (1 of 158) of reports.

H260 (99.4%): In contact with water releases flammable gases which may ignite spontaneously [Danger Substances and mixtures which in contact with water, emit flammable gases]

H314 (99.4%): Causes severe skin burns and eye damage [Danger Skin corrosion/irritation]

H318 (71.5%): Causes serious eye damage [Danger Serious eye damage/eye irritation]

P223, P231+P232, P260, P264, P264+P265, P280, P301+P330+P331, P302+P335+P334, P302+P361+P354, P304+P340, P305+P354+P338, P316, P317, P321, P363, P370+P378, P402+P404, P405, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 158 reports by companies from 7 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Reported as not meeting GHS hazard criteria per 1 of 158 reports by companies.

There are 6 notifications provided by 157 of 158 reports by companies with hazard statement code(s).

Information may vary between notifications depending on impurities, additives, and other factors. The percentage value in parenthesis indicates the notified classification ratio from companies that provide hazard codes. Only hazard codes with percentage values above 10% are shown. For more detailed information, please visit ECHA C&L website.

Section 4. First-Aid Measures

Excerpt from ERG Guide 138 [Substances - Water-Reactive (Emitting Flammable Gases)]:

Refer to the "General First Aid" section. Specific First Aid: In case of contact with substance, wipe from skin immediately; flush skin or eyes with running water for at least 20 minutes. (ERG, 2024)

General First Aid:

· Call 911 or emergency medical service.

· Ensure that medical personnel are aware of the material(s) involved, take precautions to protect themselves and avoid contamination.

· Move victim to fresh air if it can be done safely.

· Administer oxygen if breathing is difficult.

· If victim is not breathing:

-- DO NOT perform mouth-to-mouth resuscitation; the victim may have ingested or inhaled the substance.

-- If equipped and pulse detected, wash face and mouth, then give artificial respiration using a proper respiratory medical device (bag-valve mask, pocket mask equipped with a one-way valve or other device).

-- If no pulse detected or no respiratory medical device available, provide continuous compressions. Conduct a pulse check every two minutes or monitor for any signs of spontaneous respirations.

· Remove and isolate contaminated clothing and shoes.

· For minor skin contact, avoid spreading material on unaffected skin.

· In case of contact with substance, remove immediately by flushing skin or eyes with running water for at least 20 minutes.

· For severe burns, immediate medical attention is required.

· Effects of exposure (inhalation, ingestion, or skin contact) to substance may be delayed.

· Keep victim calm and warm.

· Keep victim under observation.

· For further assistance, contact your local Poison Control Center.

· Note: Basic Life Support (BLS) and Advanced Life Support (ALS) should be done by trained professionals.

Specific First Aid:

· In case of contact with substance, wipe from skin immediately; flush skin or eyes with running water for at least 20 minutes.

In Canada, an Emergency Response Assistance Plan (ERAP) may be required for this product. Please consult the shipping paper and/or the "ERAP" section.

Section 5. Fire-Fighting Measures

Excerpt from ERG Guide 138 [Substances - Water-Reactive (Emitting Flammable Gases)]:

DO NOT USE WATER OR FOAM.

SMALL FIRE: Dry chemical, soda ash, lime or sand.

LARGE FIRE: DRY sand, dry chemical, soda ash or lime or withdraw from area and let fire burn. If it can be done safely, move undamaged containers away from the area around the fire.

FIRE INVOLVING METALS OR POWDERS (ALUMINUM, LITHIUM, MAGNESIUM, ETC.): Use dry chemical, DRY sand, sodium chloride powder, graphite powder or class D extinguishers; in addition, for Lithium you may use Lith-X® powder or copper powder. Also, see ERG Guide 170.

FIRE INVOLVING TANKS, RAIL TANK CARS OR HIGHWAY TANKS: Fight fire from maximum distance or use unmanned master stream devices or monitor nozzles. Do not get water inside containers. Cool containers with flooding quantities of water until well after fire is out. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks in direct contact with flames. (ERG, 2024)

Section 6. Accidental Release Measures

· CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper not available or no answer, refer to appropriate telephone number listed on the inside back cover.

· Keep unauthorized personnel away.

· Stay upwind, uphill and/or upstream.

· Ventilate closed spaces before entering, but only if properly trained and equipped.

· ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area.

· Do not touch or walk through spilled material.

· Stop leak if you can do it without risk.

· Use water spray to reduce vapors or divert vapor cloud drift. Avoid allowing water runoff to contact spilled material.

· DO NOT GET WATER on spilled substance or inside containers.

Small Spill

· Cover with DRY earth, DRY sand or other non-combustible material followed with plastic sheet to minimize spreading or contact with rain.

· Dike for later disposal; do not apply water unless directed to do so.

Powder Spill

· Cover powder spill with plastic sheet or tarp to minimize spreading and keep powder dry.

· DO NOT CLEAN-UP OR DISPOSE OF, EXCEPT UNDER SUPERVISION OF A SPECIALIST.

Excerpt from ERG Guide 138 [Substances - Water-Reactive (Emitting Flammable Gases)]:

IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids.

LARGE SPILL: Consider initial downwind evacuation for at least 300 meters (1000 feet).

FIRE: If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2024)

Immediate precautionary measure

· Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids.

Large Spill

· Consider initial downwind evacuation for at least 300 meters (1000 feet).

· If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions.

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal, aquatic, and plant life; and conformance with environmental and public health regulations.

Section 7. Handling and Storage

Excerpt from ERG Guide 138 [Substances - Water-Reactive (Emitting Flammable Gases)]:

ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area. Do not touch or walk through spilled material. Stop leak if you can do it without risk. Use water spray to reduce vapors or divert vapor cloud drift. Avoid allowing water runoff to contact spilled material. DO NOT GET WATER on spilled substance or inside containers.

SMALL SPILL: Cover with DRY earth, DRY sand or other non-combustible material followed with plastic sheet to minimize spreading or contact with rain. Dike for later disposal; do not apply water unless directed to do so.

POWDER SPILL: Cover powder spill with plastic sheet or tarp to minimize spreading and keep powder dry. DO NOT CLEAN-UP OR DISPOSE OF, EXCEPT UNDER SUPERVISION OF A SPECIALIST. (ERG, 2024)

Keep immersed in mineral oil.

Section 8. Exposure Controls / Personal Protection

· Wear positive pressure self-contained breathing apparatus (SCBA).

· Wear chemical protective clothing that is specifically recommended by the manufacturer when there is NO RISK OF FIRE.

· Structural firefighters' protective clothing provides thermal protection but only limited chemical protection.

5.6 [mg/m3]

61 [mg/m3]

370 [mg/m3]

· DO NOT USE WATER OR FOAM.

Small Fire

· Dry chemical, soda ash, lime or sand.

Large Fire

· DRY sand, dry chemical, soda ash or lime or withdraw from area and let fire burn.

· If it can be done safely, move undamaged containers away from the area around the fire.

Fire Involving Metals or Powders (Aluminum, Lithium, Magnesium, etc.)

· Use dry chemical, DRY sand, sodium chloride powder, graphite powder or class D extinguishers; in addition, for Lithium you may use Lith-X® powder or copper powder. Also, see GUIDE 170.

Fire Involving Tanks, Rail Tank Cars or Highway Tanks

· Fight fire from maximum distance or use unmanned master stream devices or monitor nozzles.

· Do not get water inside containers.

· Cool containers with flooding quantities of water until well after fire is out.

· Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank.

· ALWAYS stay away from tanks in direct contact with flames.

Excerpt from ERG Guide 138 [Substances - Water-Reactive (Emitting Flammable Gases)]:

Wear positive pressure self-contained breathing apparatus (SCBA). Wear chemical protective clothing that is specifically recommended by the manufacturer when there is NO RISK OF FIRE. Structural firefighters' protective clothing provides thermal protection but only limited chemical protection. (ERG, 2024)

Section 9. Physical and Chemical Properties

Cesium appears as a soft metallic solid. Melts at 85 °F. Causes burns to skin and eyes.

Shiny crystals or silver metal; [Sax] Stored immersed in mineral oil; [Merck Index]

Silvery white, soft, ductile metal

Liquid (slightly above room temperature)

671 °C @760 [mm Hg]

Melting point equals 29 °C

28.44 °C

Soluble in liquid ammonia

1892 kg/cu m (solid at 17 °C); 1827 kg/cu m (liquid at 40 °C)

1.873 @25 °C

0.0000015 [mmHg]

1.5X10-6 mm Hg at 25 °C (solid)

0.686 cP at melting point

65.9 J/mol at 0.1 MPa

39.4 mN/m at melting point

Heat of fusion, 2.13 kJ/mol; specific heat, solid at 20 °C (0.217 J/g °C), liquid at bp (0.239 J/g °C), vapor at bp (0.156 J/g °C); Thermal conductivity, liquid at mp (18.4 W/m °C), vapor at bp (4.6X10-3 W/m °C); ionization potential, 3.893 eV; work function, 1.91 eV; standard electrode potential, -2.923 V; electrical conductivity, solid at mp (4.9X10+6 ohms-m)

Body-centered cubic structure; Electrical resistivity 36.6X10-6 ohm cm at 30 °C; Mohs' hardness 0.2

Emits characteristic blue color (455.5 nm) in flame.

Violent reaction with acids, halogens, and other oxidizing materials.

Violent reaction with water, moisture, or steam releases hydrogen gas which explodes. ... Incandescent reaction with nonmetals (e.g., sulfur, phosphorus).

electron density of states

dielectric constant

electromagnetic induction

optical coefficient

crystal structure

fusion temperature

Debye frequency

dielectricity

diffusion

enthalpy

radiation

electron-phonon interaction

electrode potential

effective mass

Gibbs energy

Lorenz number

Wyckoff sequence

lattice strain

positional coordinate

absorption coefficient

Section 10. Stability and Reactivity

Highly flammable. Cesium is spontaneously flammable in air at room temperature, if the surface is clean [Merck 11th ed. 1989]. Reacts with water to generate enough heat to ignite the hydrogen produced during the reaction, and to generate caustic cesium hydroxide [Mellor 2 419 1946-47].

Metals, Alkali, Very Active

Strong Reducing Agent

Water-Reactive

Pyrophoric

CESIUM reacts violently with oxidizing agents, even weaker ones. Reacts with boron trifluoride with incandescence when heated [Merck 11th ed. 1989]. Reacts explosively with maleic anhydride [Chem Safety Data Sheet SD-88 1962; Chem. Haz. Info. Series C-71 1960]. Burns in chlorine with a luminous flame [Mellor 2 Supp. 1:380 1956]. Reacts violently with most acids. Reacts violently with fluorine, chlorine, bromine and iodine. Reacts with incandescence with sulfur and phosphorus. Burns vigorously in air.

Spontaneously ignites in the atmosphere forming cesium oxides, carbonates and hydroxide.

Violent reaction with acids, halogens, and other oxidizing materials.

Violent reaction with water, moisture, or steam releases hydrogen gas which explodes. ... Incandescent reaction with nonmetals (e.g., sulfur, phosphorus).

It ignites immediately in air or oxygen. Interaction with sulfur or phosphorus attains incandescence. Interaction at ambient temperature is violent with all halogens. Cesium reacts very violently with cold water and the evolved hydrogen ignites.

Section 11. Toxicological Information

CDC-ATSDR Toxicological Profile

No indication of carcinogenicity to humans (not listed by IARC).

Developmental (effects during periods when organs are developing), Gastrointestinal (Stomach and Intestines, part of the digestive system), Neurological (Nervous System)

LD50 Mouse ip 1700 mg/kg

Basic treatment: Establish a patent airway. Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if needed. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . Anticipate seizures and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with normal saline during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 mL/kg up to 200 mL of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool ... . Cover skin burns with dry sterile dressings after decontamination ... . /Poison A and B/

Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in respiratory arrest. Positive pressure ventilation techniques with a bag valve mask device may be beneficial. Consider drug therapy for pulmonary edema ... . Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start an IV with D5W TKO /"To keep open", minimal flow rate/. Use lactated Ringer's if signs of hypovolemia are present. Watch for signs of fluid overload. For hypotension with signs of hypovolemia, administer fluid cautiously. Watch for signs of fluid overload ... . Treat seizures with diazepam (Valium) ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Poison A and B/

Section 13. Disposal Considerations

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal, aquatic, and plant life; and conformance with environmental and public health regulations.

Section 14. Transport Information

/GUIDE 138: SUBSTANCES - WATER-REACTIVE (Emitting Flammable Gases)/ Fire or Explosion: Produce flammable gases on contact with water. May ignite on contact with water or moist air. Some react vigorously or explosively on contact with water. May be ignited by heat, sparks or flames. May re-ignite after fire is extinguished. Some are transported in highly flammable liquids. Runoff may create fire or explosion hazard.

/GUIDE 138: SUBSTANCES - WATER-REACTIVE (Emitting Flammable Gases)/ Health: Inhalation or contact with vapors, substance or decomposition products may cause severe injury or death. May produce corrosive solutions on contact with water. Fire will produce irritating, corrosive and/or toxic gases. Runoff from fire control may cause pollution.

/GUIDE 138: SUBSTANCES - WATER-REACTIVE (Emitting Flammable Gases)/ Public Safety: CALL Emergency Response Telephone Number on Shipping Paper first. If Shipping Paper not available or no answer, refer to appropriate telephone number listed on the inside back cover. As an immediate precautionary measure, isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids. Keep unauthorized personnel away. Stay upwind. Keep out of low areas. Ventilate the area before entry.

/GUIDE 138: SUBSTANCES - WATER-REACTIVE (Emitting Flammable Gases)/ Protective Clothing: Wear positive pressure self-contained breathing apparatus (SCBA). Wear chemical protective clothing that is specifically recommended by the manufacturer. It may provide little or no thermal protection. Structural firefighters' protective clothing provides limited protection in fire situations ONLY; it is not effective in spill situations where direct contact with the substance is possible.

For more DOT Emergency Guidelines (Complete) data for CESIUM, ELEMENTAL (8 total), please visit the HSDB record page.

UN 1407; Caesium

IMO 4.3; Caesium

No person may /transport,/ offer or accept a hazardous material for transportation in commerce unless that person is registered in conformance ... and the hazardous material is properly classed, described, packaged, marked, labeled, and in condition for shipment as required or authorized by ... /the hazardous materials regulations (49 CFR 171-177)./

The International Maritime Dangerous Goods Code lays down basic principles for transporting hazardous chemicals. Detailed recommendations for individual substances and a number of recommendations for good practice are included in the classes dealing with such substances. A general index of technical names has also been compiled. This index should always be consulted when attempting to locate the appropriate procedures to be used when shipping any substance or article.

Dangerous When Wet

Source: PubChem CID 5354618 (NIH/NLM, public domain). Retrieved from PubChem, a public-domain chemistry database maintained by the U.S. National Library of Medicine. Last updated: 2026-08-02 09:20:07.
Disclaimer: This information is compiled for reference only and does not replace the manufacturer's official Safety Data Sheet. Always consult the supplier's SDS before handling any chemical.