Skip to Main Content

About Calcium

Calcium Bohr

Calcium is the fifth most abundant element by mass in the earth’s crust, where it is found as a component of many common minerals. Calcium carbonate is one of the most common compounds of calcium, found widely as the primary component of limestone. For millennia, humans have used limestone directly as a building material, and additionally to produce lime, which itself was widely used in building materials such as mortar. As a chemical agent, lime found historic uses in arenas such as agriculture, tanning, and glassmaking. Other widely known and used calcium minerals include marble, a type of rock resulting from the metamorphosis of limestone, and gypsum, which is composed of calcium sulfate. Though calcium is ubiquitous in these mineral forms, the metallic form is so highly reactive that it is not found in nature, and was not produced chemically until 1808. Sir Humphry Davy accomplished the production of a calcium-mercury amalgam through electrolysis of lime in the presence of mercury oxide, and from this was able to distill pure calcium metal, which he named from the latin “calc”, meaning lime.

Calcium mineral products are still widely used in building materials, as they have been for centuries. Limestone is no longer favored as a structural material due to its tendency to be eroded by acid rain, but the crushed stone is frequently used as a base material in road building. Marble, long used both to build structures and as a sculpture medium, remains in use for these and other applications. Calcium hydroxide, often termed “builder’s lime”, is a major component of many mortars, plaster, and stucco, while calcium oxide, or quicklime, is essential for the making of cement. Gypsum is also often found in both plaster and cement, but is most notable for use as gypsum board, known more commonly as drywall.

Calcium and calcium compounds are incredibly important as chemical agents. Calcium oxide is used as a flux to remove impurities during steel refining, a use that accounts for almost a third of lime consumption. Calcium hydroxide is widely used in mining and metallurgy, both as an active agent in extracting metals from their ores and as a means to neutralize acids produced by the ores or used in their processing. Calcium hydroxide also finds use in water treatment, as well as in flue gas desulfurization, where it reacts with gaseous sulfur pollutants, preventing their release into the air. Incidentally, this use results in the production of synthetic calcium sulfate, which can be used in the manufacture of gypsum products such as drywall. Lime is additionally important in processing wood pulp into paper, refining sugar, making glass, and producing a number of other important industrial chemicals. Additionally, hydrated lime is used in drilling fluid for oil and gas drilling, and serves as a source of both calcium and alkalinity, important for removing soluble carbonate ions and controlling corrosion.

Calcium plays many essential roles in biological systems, and its compounds are therefore have important agricultural and medical uses. Agricultural lime consists of pulverized limestone, and is added to soil as a source of calcium and magnesium for plants, as well as to neutralize acidic soils. Calcium carbonate is used as an antacid, a calcium supplement, and as a phosphate binder in the treatment of patients with renal failure. As a safe and relatively inert compound, it also is used as a filler in tablets and other forms of pharmaceuticals. Additionally, hydroxyapatite, the form of calcium found in bones, is often used to coat medical implants in order to promote integration of the implant with existing bone.

There are many other calcium compounds that play important roles in industry. Calcium hypochlorite is a common bleaching agent. Calcium phosphate is used in the production of fertilizer. Calcium carbide was once used in carbide lamps, but today is mostly important for production of acetylene, from which PVC is mate, and in steelmaking. Calcium phosphide is found in pyrotechnic applications such as fireworks, flares, and incindiary bombs. Calcium chloride is a desiccant and deicing agent, while calcium silicate is used as an alternative to asbestos for high-temperature insulation.

Heating calcium-rich limestone decomposes the carbonate, producing calcium oxide, or quicklime. The addition of water to quicklime produces calcium hydroxide, which is often termed slaked or hydrated lime. Most industrial calcium products use one of these as raw material, with the exception of those products that require the use of gypsum. Gypsum may be mined, or may be recovered from industrial processes where it accumulates as a byproduct. Calcium metal has comparatively few uses, but when needed is produced by mixing calcium oxide with fine particles of aluminum, and then heating the mixture in a vacuum.


+ Open All
- Close All

High Purity (99.999%) Calcium (Ca) Sputtering Target High Purity (99.999%) Calcium Oxide (CaO) Powder Calcium's primary commercial application is as a reducing agent in the production of other metals. In iron and steel production it is added to the melt to remove oxygen, sulfur and carbon. Calcium is also used in small doses in alloys of copper and beryllium. Various calcium compounds have wide application in food, pharmaceutical and cosmetics. It is also used in dietary supplements because it has been shown to improve bone and dental health. Calcium is available as metal and compounds with purities from 99% to 99.999% (ACS grade to ultra-high purity). Oxides tend to be insoluble. Fluorides are another insoluble form for uses in which oxygen is undesirable such as metallurgy, chemical and physical vapor deposition and in some optical coatings. Calcium is also available in soluble forms including chlorides, nitrates and acetates. These compounds can be manufactured as solutions at specified stoichiometries.

Calcium Properties

Calcium (Ca) atomic and molecular weight, atomic number and elemental symbolCalcium is a Block S, Group 2, Period 4 element. The number of electrons in each of Calcium's shells is 2, 8, 8, 2 and its electron configuration is [Ar] 4s2. Calcium Bohr ModelThe calcium atom has a radius of and its Van der Waals radius is In its elemental form, CAS 7440-70-2, calcium has a dull gray-silver appearance. Calcium is a reactive, soft metal that is a member of the alkaline earth elements. It is found in the minerals dolomite, gypsum, plagioclases, amphiboles, pyroxenes and garnets. Calcium was discovered and first isolated by Sir Humphry Davy in 1808. The name calcium originates from the Latin word 'calics' meaning lime.

Symbol: Ca
Atomic Number: 20
Atomic Weight: 40.078
Element Category: alkaline earth metal
Group, Period, Block: 2, 4, s
Color: silvery white/ gray
Other Names: Cálcio, Kalcium
Melting Point: 842 °C, 1547.6 °F, 1115.15 K
Boiling Point: 1484 °C, 2703.2 °F, 1757.15 K
Density: 1.55 g/cm3
Liquid Density @ Melting Point: 1.378 g/cm3
Density @ 20°C: 1.55 g/cm3
Density of Solid: 1550 kg·m3
Specific Heat: 0.156 Cal/g/K @ 25°C
Superconductivity Temperature: N/A
Triple Point: N/A
Critical Point: N/A
Heat of Fusion (kJ·mol-1): 9.33
Heat of Vaporization (kJ·mol-1): 150.6
Heat of Atomization (kJ·mol-1): 177.74
Thermal Conductivity: 2.01 W/cm/K @ 298.2 K
Thermal Expansion: (25 °C) 22.3 µm·m-1·K-1
Electrical Resistivity: 3.91 µΩ·cm @ 0 °C
Tensile Strength: N/A
Molar Heat Capacity: 25.929 J·mol-1·K-1
Young's Modulus: 20 GPa
Shear Modulus: 7.4 GPa
Bulk Modulus: 17 GPa
Poisson Ratio: 0.31
Mohs Hardness: 1.75
Vickers Hardness: N/A
Brinell Hardness: 167 MPa
Speed of Sound: (20 °C) 3810 m·s-1
Pauling Electronegativity: 1
Sanderson Electronegativity: 0.95
Allred Rochow Electronegativity: 1.04
Mulliken-Jaffe Electronegativity: 1.08 (sp orbital)
Allen Electronegativity: 1.034
Pauling Electropositivity: 3
Reflectivity (%): N/A
Refractive Index: N/A
Electrons: 20
Protons: 20
Neutrons: 20
Electron Configuration: [Ar] 4s2
Atomic Radius: 197 pm
Atomic Radius, non-bonded (Å): 2.31
Covalent Radius: 176±10 pm
Covalent Radius (Å): 1.74
Van der Waals Radius: 231 pm
Oxidation States: 2, 1 (strongly basic oxide)
Phase: Solid
Crystal Structure: face-centered cubic
Magnetic Ordering: diamagnetic
Electron Affinity (kJ·mol-1) 2.368
1st Ionization Energy: 589.83 kJ·mol-1
2nd Ionization Energy: 1145.46 kJ·mol-1
3rd Ionization Energy: 4912.40 kJ·mol-1
CAS Number: 7440-70-2
EC Number: 231-179-5
MDL Number: MFCD00085314
Beilstein Number: 4241647
SMILES Identifier: [Ca]
InChI Identifier: InChI=1S/Ca
PubChem CID: 5460341
ChemSpider ID: 4573905
Earth - Total: 1.54%
Mercury - Total: 1.18%
Venus - Total:  1.61% 
Earth - Seawater (Oceans), ppb by weight: 4220
Earth - Seawater (Oceans), ppb by atoms: 650
Earth -  Crust (Crustal Rocks), ppb by weight: 50000000
Earth -  Crust (Crustal Rocks), ppb by atoms: 26000000
Sun - Total, ppb by weight: 70000
Sun - Total, ppb by atoms: 2000
Stream, ppb by weight: 1500
Stream, ppb by atoms: 38
Meterorite (Carbonaceous), ppb by weight: 11000000
Meterorite (Carbonaceous), ppb by atoms: 5200000
Typical Human Body, ppb by weight: 14000000
Typical Human Body, ppb by atom: 2200000
Universe, ppb by weight: 70000
Universe, ppb by atom: 2000
Discovered By: Humphry Davy
Discovery Date: 1808
First Isolation: Humphry Davy (1808)

Health, Safety & Transportation Information for Calcium

Calcium is non-toxic and is an essential metal for living organisms. Safety data for Calcium and its compounds can vary widely depending on the form. For potential hazard information, toxicity, and road, sea and air transportation limitations, such as DOT Hazard Class, DOT Number, EU Number, NFPA Health rating and RTECS Class, please see the specific material or compound referenced in the Products tab. The below information applies to elemental (metallic) Calcium.

Safety Data
Signal Word Danger
Hazard Statements H261
Hazard Codes F
Risk Codes 15
Safety Precautions 8-24/25-43
RTECS Number N/A
Transport Information UN 1401 4.3/PG 2
WGK Germany 1
Globally Harmonized System of
Classification and Labelling (GHS)
Review and Print SDS for Calcium Metal


Date Created: 05/15/2015
Date Revised: 05/15/2015


Product Name: Calcium Metal

Product Number: All applicable American Elements product codes, e.g. CA-M-02, CA-M-03, CA-M-04, CA-M-05

CAS #: 7440-70-2

Relevant identified uses of the substance: Scientific research and development

Supplier details:
American Elements
1093 Broxton Ave. Suite 2000
Los Angeles, CA 90024
Tel: +1 310-208-0551
Fax: +1 310-208-0351

Emergency telephone number:
Domestic, North America +1 800-424-9300
International +1 703-527-3887


Classification of the substance or mixture
Classification according to Regulation (EC) No 1272/2008
GHS02 Flame
Water-react. 2 H261 In contact with water releases flammable gas.
Classification according to Directive 67/548/EEC or Directive 1999/45/EC
F; Highly flammable
R15: Contact with water liberates extremely flammable gases.
Information concerning particular hazards for human and environment:
Not applicable
Hazards not otherwise classified
No information known.
Label elements
Labelling according to Regulation (EC) No 1272/2008
The substance is classified and labeled according to the CLP regulation.
Hazard pictograms

Flame - GHS02

Signal word
Hazard statements
H261 In contact with water releases flammable gas.
Precautionary statements
P231+P232 Handle under inert gas. Protect from moisture.
P280 Wear protective gloves/protective clothing/eye protection/face protection.
P233 Keep container tightly closed.
P370+P378 In case of fire: Use for extinction: CO2, sand, extinguishing powder.
P402+P404 Store in a dry place. Store in a closed container.
P501 Dispose of contents/container in accordance with local/regional/national/international regulations.
WHMIS classification
B6 - Reactive flammable material
Classification system
HMIS ratings (scale 0-4)
(Hazardous Materials Identification System)
Health (acute effects) = 1
Flammability = 3
Physical Hazard = 2
Other hazards
Results of PBT and vPvB assessment
PBT: Not applicable.
vPvB: Not applicable.


Chemical characterization: Substances
CAS# Description:
7440-70-2 Calcium
Identification number(s):
EC number: 231-179-5
Index number: 020-001-00-X


Description of first aid measures
After inhalation
Supply fresh air. If required, provide artificial respiration. Keep patient warm.
Seek immediate medical advice.
After skin contact
Immediately wash with water and soap and rinse thoroughly.
Seek immediate medical advice.
After eye contact
Rinse opened eye for several minutes under running water. Then consult a doctor.
After swallowing
Seek medical treatment.
Information for doctor
Most important symptoms and effects, both acute and delayed
No further relevant information available.
Indication of any immediate medical attention and special treatment needed
No further relevant information available


Extinguishing media
Suitable extinguishing agents
Special powder for metal fires. Do not use water.
For safety reasons unsuitable extinguishing agents
Special hazards arising from the substance or mixture
If this product is involved in a fire, the following can be released:
Calcium oxide
Advice for firefighters
Protective equipment:
Wear self-contained respirator.
Wear fully protective impervious suit.


Personal precautions, protective equipment and emergency procedures
Wear protective equipment. Keep unprotected persons away.
Ensure adequate ventilation
Keep away from ignition sources
Environmental precautions:
Do not allow material to be released to the environment without proper governmental permits.
Do not allow product to reach sewage system or any water course.
Do not allow to penetrate the ground/soil.
Methods and material for containment and cleaning up:
Keep away from ignition sources.
Ensure adequate ventilation.
Do not flush with water or aqueous cleansing agents
Prevention of secondary hazards:
Keep away from ignition sources.
Reference to other sections
See Section 7 for information on safe handling
See Section 8 for information on personal protection equipment.
See Section 13 for disposal information.


Precautions for safe handling
Handle under dry protective gas.
Keep container tightly sealed.
Store in cool, dry place in tightly closed containers.
Ensure good ventilation at the workplace.
Reacts violently with water
Information about protection against explosions and fires:
Protect from humidity and water.
Conditions for safe storage, including any incompatibilities
Requirements to be met by storerooms and receptacles:
No special requirements.
Information about storage in one common storage facility:
Store away from air.
Store away from water/moisture.
Further information about storage conditions:
Store under dry inert gas.
Keep container tightly sealed.
Store in cool, dry conditions in well sealed containers.
Protect from humidity and water.
Specific end use(s)
No further relevant information available.


Additional information about design of technical systems:
Properly operating chemical fume hood designed for hazardous chemicals and
having an average face velocity of at least 100 feet per minute.
Control parameters
Components with limit values that require monitoring at the workplace:
The product does not contain any relevant quantities of materials with critical values
that have to be monitored at the workplace.
Additional information: No data
Exposure controls
Personal protective equipment
General protective and hygienic measures
The usual precautionary measures for handling chemicals should be followed.
Keep away from foodstuffs, beverages and feed.
Remove all soiled and contaminated clothing immediately.
Wash hands before breaks and at the end of work.
Maintain an ergonomically appropriate working environment.
Breathing equipment:
Use suitable respirator when high concentrations are present.
Recommended filter device for short term use:
Use a respirator with type P100 (USA) or P3 (EN 143) cartridges as a backup to engineering controls. Risk assessment should be performed to determine if air-purifying respirators are appropriate. Only use equipment tested and approved under appropriate government standards.
Protection of hands: Impervious gloves
Check protective gloves prior to each use for their proper condition.
The selection of suitable gloves not only depends on the material, but also on quality. Quality will vary from manufacturer to manufacturer.
Material of gloves
Nitrile rubber, NBR
Penetration time of glove material (in minutes)
Glove thickness
0.11 mm
Eye protection: Safety glasses
Full face protection
Body protection: Protective work clothing.


Information on basic physical and chemical properties
General Information
Form: Solid in various forms
Color: Silvery-white
Odor: Odorless
Odor threshold: Not determined.
pH-value: Not applicable.
Change in condition
Melting point/Melting range: 842 °C (1548 °F)
Boiling point/Boiling range: 1440 °C (2624 °F)
Sublimation temperature / start: Not determined
Flammability (solid, gaseous): Contact with water liberates extremely flammable gases.
Ignition temperature: Not determined
Decomposition temperature: Not determined
Auto igniting: Not determined.
Danger of explosion: Not determined.
Explosion limits:
Lower: Not determined
Upper: Not determined
Vapor pressure at 20 °C (68 °F): 0 hPa
Density at 20 °C (68 °F): 1.54 g/cm³ (12.851 lbs/gal)
Bulk density at 20 °C (68 °F): 700 kg/m³
Relative density: Not determined.
Vapor density: Not applicable.
Evaporation rate: Not applicable.
Solubility in / Miscibility with Water: Contact with water releases flammable gases
Partition coefficient (n-octanol/water): Not determined.
dynamic: Not applicable.
kinematic: Not applicable.
Other information
No further relevant information available


In contact with water releases flammable gases which may ignite spontaneously.
Chemical stability
Stable under recommended storage conditions.
Thermal decomposition / conditions to be avoided:
Decomposition will not occur if used and stored according to specifications.
Possibility of hazardous reactions
Contact with water releases flammable gases
Conditions to avoid
No further relevant information available.
Incompatible materials:
Hazardous decomposition products:
Calcium oxide


Information on toxicological effects
Acute toxicity: No effects known.
LD/LC50 values that are relevant for classification: No data
Skin irritation or corrosion: May cause irritation
Eye irritation or corrosion: May cause irritation
Sensitization: No sensitizing effects known.
Germ cell mutagenicity: No effects known.
Carcinogenicity: No classification data on carcinogenic properties of this material is available from the EPA, IARC, NTP, OSHA or ACGIH.
Reproductive toxicity: No effects known.
Specific target organ system toxicity - repeated exposure: No effects known.
Specific target organ system toxicity - single exposure: No effects known.
Aspiration hazard: No effects known.
Subacute to chronic toxicity: No effects known.
Additional toxicological information: To the best of our knowledge the acute and chronic toxicity of this substance is not fully known.
Carcinogenic categories
OSHA-Ca (Occupational Safety & Health Administration)
Substance is not listed.


Aquatic toxicity:
No further relevant information available.
Persistence and degradability
No further relevant information available.
Bioaccumulative potential
No further relevant information available.
Mobility in soil
No further relevant information available.
Additional ecological information:
General notes:
Do not allow material to be released to the environment without proper governmental permits.
Avoid transfer into the environment.
Results of PBT and vPvB assessment
PBT: Not applicable.
vPvB: Not applicable.
Other adverse effects
No further relevant information available.


Waste treatment methods
Consult state, local or national regulations to ensure proper disposal.
Uncleaned packagings:
Disposal must be made according to official regulations


UN proper shipping name
Transport hazard class(es)
4.2 Substances liable to spontaneous combustion.
4.3 (W2) Substances which, in contact with water, emit flammable gases
4.2 Substances liable to spontaneous combustion.
4.3 Substances which, in contact with water, emit flammable gases.
Packing group
Environmental hazards: Not applicable.
Special precautions for user
Warning: Substances which, in contact with water, emit flammable gases
EMS Number:
Transport in bulk according to Annex II of MARPOL73/78 and the IBC Code
Not applicable.
Transport/Additional information:
Marine Pollutant (DOT):
UN "Model Regulation":
UN1401, Calcium, 4.3, II


Safety, health and environmental regulations/legislation specific for the substance or mixture
National regulations
All components of this product are listed in the U.S. Environmental Protection Agency Toxic Substances Control Act Chemical substance Inventory.
All components of this product are listed on the Canadian Domestic Substances List (DSL).
SARA Section 313 (specific toxic chemical listings)
Substance is not listed.
California Proposition 65
Prop 65 - Chemicals known to cause cancer
Substance is not listed.
Prop 65 - Developmental toxicity
Substance is not listed.
Prop 65 - Developmental toxicity, female
Substance is not listed.
Prop 65 - Developmental toxicity, male
Substance is not listed.
Information about limitation of use:
For use only by technically qualified individuals.
Other regulations, limitations and prohibitive regulations
Substance of Very High Concern (SVHC) according to the REACH Regulations (EC) No. 1907/2006.
Substance is not listed.
The conditions of restrictions according to Article 67 and Annex XVII of the Regulation (EC) No 1907/2006 (REACH) for the manufacturing, placing on the market and use must be observed.
Substance is not listed.
Annex XIV of the REACH Regulations (requiring Authorisation for use)
Substance is not listed.
REACH - Pre-registered substances
Substance is listed.
Chemical safety assessment:
A Chemical Safety Assessment has not been carried out.


Safety Data Sheet according to Regulation (EC) No. 1907/2006 (REACH). The above information is believed to be correct but does not purport to be all inclusive and shall be used only as a guide. The information in this document is based on the present state of our knowledge and is applicable to the product with regard to appropriate safety precautions. It does not represent any guarantee of the properties of the product. American Elements shall not be held liable for any damage resulting from handling or from contact with the above product. See reverse side of invoice or packing slip for additional terms and conditions of sale. COPYRIGHT 1997-2016 AMERICAN ELEMENTS. LICENSED GRANTED TO MAKE UNLIMITED PAPER COPIES FOR INTERNAL USE ONLY.

Calcium Isotopes

Calcium has five stable isotopes: 40Ca, 42Ca, 43Ca, 44Ca and 46Ca

Nuclide Isotopic Mass Half-Life Mode of Decay Nuclear Spin Magnetic Moment Binding Energy (MeV) Natural Abundance
(% by atom)
34Ca 34.01412(32)# <35 ns p to 33K 0+ N/A 239.19 MeV -
35Ca 35.00494(21)# 25.7(2) ms ß+ to 35K; ß+ + p to 34Ar 1/2+# N/A 256.59 MeV -
36Ca 35.99309(4) 102(2) ms ß+ + p to 35Ar; ß+ to 36K 0+ N/A 274.91 MeV -
37Ca 36.985870(24) 181.1(10) ms ß+ + p to 36Ar; ß+ to 37K (3/2+) N/A 290.45 MeV -
38Ca 37.976318(5) 440(8) ms EC to 38K 0+ N/A 306.91 MeV -
39Ca 38.9707197(20) 859.6(14) ms EC to 39K 3/2+ N/A 320.58 MeV -
40Ca 39.96259098(22) Observationally Stable - 0+ 0 336.11 96.941
41Ca 40.96227806(26) 1.02(7)E+5 y EC to 41K 7/2- -1.595 344.19 -
42Ca 41.95861801(27) STABLE - 0+ 0 355.99 0.647
43Ca 42.9587666(3) STABLE - 7/2- -1.31727 364.07 0.135
44Ca 43.9554818(4) STABLE - 0+ 0 374.95 2.086
45Ca 44.9561866(4) 162.67(25) d ß- to 45Sc 7/2- -1.327 382.09 -
46Ca 45.9536926(24) Observationally Stable - 0+ 0 392.97 0.004
47Ca 46.9545460(24) 4.536(3) d ß- to 47Sc 7/2- -1.38 400.11 -
48Ca 47.952534(4) 43(38)E+18 y - to 48Ti 0+ 0 410.05 0.187
49Ca 48.955674(4) 8.718(6) min ß- to 49Sc 3/2- N/A 415.34 -
50Ca 49.957519(10) 13.9(6) s ß- to 50Sc 0+ N/A 421.55 -
51Ca 50.9615(1) 10.0(8) s ß- to 51Sc; ß- + n to 50Sc (3/2-)# N/A 425.91 -
52Ca 51.96510(75) 4.6(3) s ß- to 52Sc; ß- + n to 51Sc 0+ N/A 430.26 -
53Ca 52.97005(54)# 90(15) ms ß- to 53Sc; ß- + n to 52Sc 3/2-# N/A 433.68 MeV
54Ca 53.97435(75)# 50# ms [>300 ns] ß- + n to 53Sc; ß- to 54Sc 0+ N/A 438.03 MeV
55Ca 54.98055(75)# 30# ms [>300 ns] ß- to 55Sc 5/2-# N/A 440.52 MeV
56Ca 55.98557(97)# 10# ms [>300 ns] ß- to 56Sc 0+ N/A 443.94 MeV
57Ca 56.99236(107)# 5# ms ß- to 57Sc; ß- + n to 56Sc 5/2-# N/A 445.50 MeV