| Identification | Back Directory | [Name]
CALCIUM | [CAS]
14452-75-6 | [Synonyms]
CALCIUM
(E)-hept-2-enoate
Ca Standard Solution
3-(4-methylphenyl)butanoate
2,6,6-trimethyloxane-2-carboxylate
calmodulin-dependent protein kinase-1α
(5E,7E)-4-oxo-8-phenylocta-5,7-dienoate
calmodulin-dependent protein kinase-Ⅱ ELISA Kit
calmodulin-dependent protein kinase-1α ELISA Kit
4-[[4-[benzyl(ethyl)amino]phenyl]-[4-[benzyl(ethyl)azaniumylidene]cyclohexa-2,5-dien-1-ylidene]methyl]benzene-1,3-disulfonate
4-[[4-[benzyl(ethyl)amino]phenyl]-[4-[benzyl(ethyl)azaniumylidene]cyclohexa-2,5-dien-1-ylidene]methyl]-6-hydroxybenzene-1,3-disulfonate | [Molecular Formula]
Ca | [MDL Number]
MFCD00085314 | [MOL File]
14452-75-6.mol | [Molecular Weight]
40.08 |
| Chemical Properties | Back Directory | [form ]
Liquid | [color ]
Clear colorless | [Water Solubility ]
Miscible with water. | [Dielectric constant]
3.0（Ambient） | [Exposure limits]
ACGIH: TWA 2 ppm; STEL 4 ppm
OSHA: TWA 2 ppm(5 mg/m3)
NIOSH: IDLH 25 ppm; TWA 2 ppm(5 mg/m3); STEL 4 ppm(10 mg/m3) | [History]
Though lime
was prepared by the Romans in the first century under the
name calx, Calcium was not discovered until 1808. After
learning that Berzelius and Pontin prepared calcium amalgam
by electrolyzing lime in mercury, Davy was able to isolate the
impure metal. Calcium is a metallic element, fifth in abundance
in the Earth’s crust, of which it forms more than 3%. It
is an essential constituent of leaves, bones, teeth, and shells.
Never found in nature uncombined, it occurs abundantly
as limestone (CaCO3), gypsum (CaSO4·2H2O), and fluorite
(CaF2); apatite is the fluorophosphate or chlorophosphate of
calcium. Calcium has a silvery color, is rather hard, and is
prepared by electrolysis of the fused chloride to which calcium
fluoride is added to lower the melting point. Chemically it
is one of the alkaline earth elements; it readily forms a white
coating of oxide in air, reacts with water, burns with a yellowred
flame, largely forming the oxide. The metal is used as a
reducing agent in preparing other metals such as thorium,
The Elements 4-7
uranium, zirconium, etc., and is used as a deoxidizer, desulfurizer,
and inclusion modifier for various ferrous and nonferrous
alloys. It is also used as an alloying agent for aluminum,
beryllium, copper, lead, and magnesium alloys, and serves as a
“getter” for residual gases in vacuum tubes. Its natural and prepared
compounds are widely used. Quicklime (CaO), made by
heating limestone and changed into slaked lime by the careful
addition of water, is the great cheap base of the chemical
industry with countless uses. Mixed with sand it hardens as
mortar and plaster by taking up carbon dioxide from the air.
Calcium from limestone is an important element in Portland
cement. The solubility of the carbonate in water containing
carbon dioxide causes the formation of caves with stalactites
and stalagmites and is responsible for hardness in water.
Other important compounds are the carbide (CaC2), chloride
(CaCl2), cyanamide (CaCN2), hypochlorite (Ca(OCl)2), nitrate
(Ca(NO3)2), and sulfide (CaS). Calcium sulfide is phosphorescent
after being exposed to light. Natural calcium contains
six isotopes. Sixteen other radioactive isotopes are known.
Metallic calcium (99.5%) costs about $200/kg. | [Uses]
Calcium is an alkaline earth element that contributes toward bone
and teeth formation, muscle contraction, and blood clotting. it
occurs in milk, vegetables, and egg yolk. |
| Safety Data | Back Directory | [Symbol(GHS) ]
GHS02 | [Signal word ]
Danger | [Hazard statements ]
H261 | [Precautionary statements ]
P231+P232 | [RIDADR ]
UN 1401 4.3/ PGII | [RIDADR ]
UN 1855 4.2/ PGI | [HazardClass ]
4.2 | [HazardClass ]
4.3 | [PackingGroup ]
I | [PackingGroup ]
II |
| Hazard Information | Back Directory | [Description]
Calcium is the chemical element with the symbol Ca
and atomic number 20. It has an atomic weight of
40.078 g/mol. Calcium is the fifth most abundant dissolved
ion in seawater by both molarity and mass, after
Na+, Cl-, Mg2+ and SO42-. Calcium metal is quite
reactive. It readily forms a white coating of calcium
nitride (Ca3N2) in air at room temperature. It reacts
with water and the metal burns in air with an orangered
flame, forming largely the nitride, but some oxide.
In the visible portion of the spectrum of many stars,
including the Sun, strong absorption lines of singly
ionized calcium ions are evident. Prominent among
these are the H line at 3968.5 A ° and the K line at
3933.7 A°of singly ionized calcium, or Ca II. For the
Sun, and stars with low temperatures, the prominence
of the H and K lines is an indication of strong magnetic
activity in the chromosphere. Measurement of periodic
variations of these active regions can also be used to
deduce the rotational periods of these stars. | [Physical properties]
Before the nineteenth century, calcium and some other alkali earth metals were consideredminerals rather than metals because they readily formed hydroxides and, thus, were classedas alkaline substances (bases). Calcium and other alkali earth metals were mined as ores.Therefore, early chemists considered them earth elements.Calcium metal is moderately hard and has a lustrous, silvery color when freshly cut, but itsoon oxidizes to a dull gray. It is a good conductor of heat and electricity, but has few uses inthe electronics industries. Calcium is an important element for the nutrition of living organisms, particularly vertebrates. Vitamin D from foods, sunlight, and milk aids in the depositionof calcium in bones and teeth. The elemental metal is very reactive in water as it releases hydrogen from the water. It is somewhat less reactive in air. Its melting point is 839°C, its boilingpoint is 1484°C, its density is 1.54 g/cm3, and it has a cubic crystal structure. | [Isotopes]
Calcium has four stable isotopes (40Ca and 42Ca
through 44Ca), plus two more isotopes (46Ca and 48Ca)
that have such a long half-lives that for all practical
purposes they can be considered stable. It also has
a cosmogenic isotope, radioactive 44Ca, with a half-life
of 103,000 years. Unlike cosmogenic isotopes that are
produced in the atmosphere, 41Ca is produced by
neutron activation of 40Ca. Most of its production is in
the upper meter or so of the soil column, where the
cosmogenic neutron flux is still sufficiently strong.
41Ca has received much attention in stellar studies
because it decays to 41K, a critical indicator of solar
system anomalies.
A major part (97%) of naturally occurring calcium is
in the form of 40Ca. This isotope is one of the daughter
products of 40K decay, along with 40Ar. While K/Ar
dating has been used extensively in the geological
sciences, the prevalence of 40Ca in nature has impeded
its use in dating. Techniques using mass spectrometry
and a “double-spike” isotope dilution have been used
for K/Ca age dating.
The most abundant isotope, 40Ca, has a nucleus of 20
protons and 20 neutrons. This is the heaviest stable
isotope of any element known that has equal numbers
of protons and neutrons. In supernova explosions,
calcium is formed from the reaction of carbon with
various numbers of alpha particles (helium nuclei), until
this most common calcium isotope (containing 10
helium nuclei) has been formed. | [Isotopes]
There are 20 isotopes of calcium, ranging from Ca-35 to Ca-54. Of the sixstable isotopes, Ca-40 makes up 96.941% of the calcium found in the Earth’s crust, andCa-42 = 0.647%, Ca-43 = 0.135%, Ca-44 = 2.086%, Ca-46 = 0.004%, and Ca-48 =0.187% found on Earth. All the other isotopes of calcium are radioactive and are artificially produced with half-lives ranging from a few microseconds to 1×105 years.Radioactive Ca-45 emits beta particles (high-speed electrons) and has a half-life ofabout 163 days. It is used to determine the calcium levels in bones and in soils. | [Origin of Name]
Its modern name was derived from the word calcis or calx, which is
Latin for “l(fā)ime. | [Occurrence]
Calcium is the fifth most abundant element found in the Earth’s crust. It is not found asa free element, but as calcium compounds (mostly salts and oxides), which are found on alllandmasses of the world as limestone, marble, and chalk. Calcium, particularly as the compound calcium chloride (CaCl2), is found in the oceans to the extent of 0.15%.Calcium is produced by two methods. One method is the electrolysis of calcium chloride(Ca++ + 2Cl- → CaCl2) as the electrolyte at a temperature of ?800°C, during which processmetallic calcium cations (Ca++) are deposited at the cathode as elemental calcium metal.Calcium can also be produced through a thermal process under very low pressure (vacuum)in which lime is reduced by using aluminum.In addition to limestone, calcium is also found in other rocks, coral, shells, eggshells, bones,teeth, and stalactites and stalagmites. | [Characteristics]
Finely powdered calcium metal is flammable in air because it liberates hydrogen from themoisture. It can be extremely reactive in water but can be dissolved in acids. Calcium is harderthan sodium metal, but softer than aluminum. In its elemental form it can be machined (cuton a lathe), extruded (pushed through a die), and drawn (stretched into rods or wires).Calcium is present in a number of products used in our everyday lives. It is found inclassroom chalk, teeth, and bones. About 2% of the human body consists of various forms ofcalcium compounds. Calcium is an essential inorganic element (usually in compound form)for plant and animal life. | [Definition]
A moderately soft, low-melting reactive metal; the third element in group 2 (formerly IIA) of the periodic table. The electronic configuration is that of argon with an additional pair of 4s electrons.
Calcium is widely distributed in the Earth’s crust and is the third most abundant element. Large deposits occur as chalk or marble, CaCO3; gypsum, CaSO4. 2H2O; anhydrite, CaSO4; fluorspar, CaF; and apatite, CaF2.Ca3(PO4)3. However sufficiently large quantities of calcium chloride are available as waste from the Solvay process to satisfy industrial requirements for the metal, which is produced by electrolysis of the fused salt. Large quantities of lime, Ca(OH)2, and quicklime, CaO, are produced by decomposition of the carbonate for use in both building and agriculture. Several calcium minerals are mined as a source of other substances. Thus, limestone is a cheap source of carbon dioxide, gypsum and anhydrite are used in the manufacture of sulfuric acid, phosphate rock for phosphoric acid, and fluorspar for a range of fluorochemicals.
Calcium has a low ionization potential and a relatively large atomic radius. It is therefore a very electropositive element. The metal is very reactive and the compounds contain the divalent ion Ca2+. Calcium forms the oxide (CaO), a white ionic solid, on burning in air, but for practical purposes the oxide is best prepared by heating the carbonate, which decomposes at about 800°C. Both the oxide and the metal itself react with water to give the basic hydroxide (Ca(OH)2). On heating with nitrogen, sulfur, or the halogens, calcium reacts to form the nitride (Ca3N2), sulfide (CaS), or the halides (CaX2). Calcium also reacts directly with hydrogen to give the hydride CaH2 and borides, arsenides, carbides, and silicides can be prepared in a similar way. Both the carbonate and sulfate are insoluble. Calcium salts impart a characteristic brick-red color to flames which is an aid to qualitative analysis. At ordinary temperatures calcium has the face-centered cubic structure with a transition at 450°C to the close-packed hexagonal structure. | [Definition]
calcium: Symbol Ca. A soft greymetallic element belonging togroup 2 (formerly IIA) of the periodictable; a.n. 20; r.a.m. 40.08; r.d.1.54; m.p. 839°C; b.p. 1484°C. Calciumcompounds are common in theearth’s crust; e.g. limestone and marble(CaCO3), gypsum (CaSO4.2H2O),and fluorite (CaF2). The element is extractedby electrolysis of fused calciumchloride and is used as a getterin vacuum systems and a deoxidizerin producing nonferrous alloys. It isalso used as a reducing agent in theextraction of such metals as thorium,zirconium, and uranium.
Calcium is an essential element forliving organisms, being required fornormal growth and development. Inanimals it is an important constituentof bones and teeth and ispresent in the blood, being requiredfor muscle contraction and othermetabolic processes. In plants it is aconstituent (in the form of calciumpectate) of the middle lamella. | [Indications]
Calcium is the principal extracellular electrolyte regulated
by PTH, calcitonin, and D3. Extracellular calcium
is a critical component of signal transduction across the
plasma membrane, which regulates a wide spectrum of
physiological events including muscle contraction, secretion
of neurotransmitters and hormones, and the action
of growth factors, cytokines, and protein hormones.
Intracellular calcium is an important cofactor in many
enzymatic reactions. | [Hazard]
The metallic form of calcium, particularly the powdered form, combines with water oroxidizing agents to release hydrogen that may explode, as do the other alkali metals. There aremany useful calcium compounds; some are excellent reducing agents, some are explosive, andothers are essential for life.
The radioactive isotope calcium-45 is deposited in bones and teeth as well as other plantand animal tissues. Because our bodies cannot distinguish between Ca-45 and the stable Ca-40, the radioactive isotope Ca-45 is used as a tracer to study diseased bone and tissue. At thesame time, a massive overexposure to Ca-45 can displace the stable form of Ca-40 in animalsand can cause radiation sickness or even death.
A few calcium compounds, when in powder or vapor form, are toxic when ingested orinhaled. | [Agricultural Uses]
Calcium (Ca), an element essential for the growth of
living organisms, is a soft grey metallic element
belonging to Group 2 (formerly Ⅱ A) of the Periodic
Table. It is an important constituent of bones
and teeth in animals and is present in blood. It is required
for muscle contraction and other metabolic processes. In
plants, it is a constituent of the middle lamella and is
essential for plant cell elongation, cell division and
various anabolic and catabolic processes.
Calcium is an essential secondary plant nutrient. It is
absorbed by plant roots as calcium ions and supplied to
the root surface by mass flow and root interception. In
cells, calcium levels are micromolar, whereas externally
they are millimolar, facilitating a major role in metabolic
control. Calcium levels directly control many enzyme
reactions and enhance the uptake of nitrate, thus
becoming interrelated with nitrogen metabolism.
Calcium also facilitates the uptake of potassium ions
preferentially over sodium ions. Therefore, an optimum
ratio of potassium to calcium is important for a favorable
water balance in plants.
Calcium is generally an immobile element in plants.
Calcium concentration usually averages to about 33
ppm in the soil solution. A level of 15 ppm is adequate for
a high corn yield. A higher concentration or excess of
calcium in soil can cause deficiency of potassium and
some micronutrients, particularly zinc. Crops like
alfalfa, cabbage, Potato and Sugar beet9 need higher
amounts of calcium.
Calcium content varies widely in soil. Plagioclase
mineral anorthite is the most important primary source of
calcium. The availability of calcium from soil to plants is
determined by many factors, such as the total calcium
content, soil pH, cation exchange capacity (CEC),
calcium percentage saturation, type of soil colloid, ratio
of calcium to other cations in solution, etc. Highly acidic
soils impede the uptake of calcium ions. As the calcium
percentage saturation decreases relative to the total CEC,
the amount of calcium ions absorbed by the plant
decreases.
Many crops respond to calcium applications when the
exchangeable calcium ion saturation falls below 25%.
The 2: 1 clays (meaning, a lattice with 2 silica sheets for 1
alumina sheet) require a higher calcium ion saturation
than 1 : 1 clays (a lattice with 1 silica sheet for 1 alumina
sheet). An increased aluminum ion concentration in the
soil solution reduces calcium uptake by crops such as
corn, cotton, soybean and wheat. The calcium supply for
most crops is considered adequate when the soil calcium
to cation ratio is between 0.10 and 0.15. Ammonium,
potassium, magnesium, manganese and aluminum ions
suppress the calcium ion uptake by plants, whereas
nitrate ions enhance it.
Calcium deficiency leads to a decrease in the
development of terminal shoot buds and apical root tips,
thereby inhibiting plant growth. Calcium deficiency also
causes distortion of new leaves; in maize, for instance,
the deficiency prevents the emergence and unfolding of
new leaves and renders the tips of the existing leaves
almost colorless. A sticky gelatinous material causes the
leaves to adhere to one another.
Calcium deficiency is rare in fruits (excepting apples
which show pitting of flesh and skin) and vegetables;
however, it is seen as a disorder in the storage tissues.
The quantity of calcium lost by leaching is 75 to 200
kg/ha/yr. This loss is greater than that of sodium ions as
the quantity of calcium present in a solution is higher and
is in an exchangeable form.
Calcium is also lost or neutralized from the soil by
other routes. These are (a) rapid neutralization by acidforming
fertilizers (ammonium), (b) slow neutralization
by acid formed by carbon dioxide in water due to
decomposition of organic matter, (c) erosion, leaving
more acidic subsoil to be limed, (d) slow removal of
harvested or grazed crops, and (e) slow neutralization by
acidic rain.
Calcium is added to plants as a component of other
nutrients, particularly phosphorus, as in
superphosphates. Primary sources of liming materials
are calcium carbonate and magnesium carbonate.
Gypsum is used for supplementing calcium as a
nutrient without correcting soil acidity. Synthetic
chelates, such as ethylenediaminetetraacetic acid
(EDTA) complexes of calcium containing 3 to 5%
calcium, are used as fertilizers both for soil and foliar
applications.
The uptake of calcium is progressively reduced by the
presence of ammonium, magnesium, potassium and
sodium ions, in that order. The foliar calcium to
magnesium ratio of 2: 1 and potassium to calcium ratio of
4:l are considered optimum for plant growth.
Phosphorus favors calcium uptake under acidic
conditions. A pH increase after excessive liming results
indeficiencies of iron, manganese, boron or zinc, leading
to subsequent chlorosis. Calcium and boron exhibit a
synergistic effect in reducing plant disorders. | [Pharmaceutical Applications]
Calcium is mostly found in limestone and its related forms, such as chalk, and marble and lime (CaO). Calcium is the most abundant inorganic element in the human body and is an essential key for many physiological
processes. Calcium ions are a critical
factor in several life-defining biochemical processes as well as in the endocrine, neural and renal aspects of
blood pressure homeostasis.
Calcium has the symbol Ca and atomic number 20 and is a soft grey alkaline earth metal. Calcium has
four stable isotopes (40Ca and 42Ca–44Ca) and the metal reacts with water with the formation of calcium
hydroxide and hydrogen. | [Industrial uses]
Calcium (symbol Ca) is a metallic elementbelonging to the group of alkaline earths. It isone of the most abundant materials, occurringin combination in limestones and calcareousclays. The metal is obtained 98.6% pure byelectrolysis of the fused anhydrous chloride. Byfurther subliming, it is obtained 99.5% pure.Calcium metal is yellowish white in color. Itoxidizes easily and, when heated in air, burnswith a brilliant white light. It has a density of1.55 g/cm3, a melting point of 838°C, and aboiling point of 1440°C. Its strong affinity for O2 and sulfur is utilized as a cleanser for nonferrous alloys. As a deoxidizer and desulfurizerit is employed in the form of lumps or sticks ofcalcium metal or in ferroalloys and Ca–Cu.
Many compounds of calcium are employedindustrially, in fertilizers, foodstuffs, and medicine.It is an essential element in the formationof bones, teeth, shells, and plants. Oyster shellsform an important commercial source of calciumfor animal feeds. They are crushed, andthe fine flour is marketed for stock feeds andthe coarse for poultry feeds. The shell is calciumcarbonate. |
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