calcium

• Description
• General information
• Physical data
• Radii
• Electronegativities
• Solid state structure
• Temperatures
• Enthalpies
• Ionization Enthalpies
• Isotopes
• Further information

Description

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.

The metal is a silvery colour and is rather hard. Chemically it is one of the alkaline earth elements; it readily forms a white coating of nitride in air, reacts with water, burns with a yellow-red flame, forming largely the nitride.

Calcium does not occur free in nature. Calcium is found mostly as limestone, gypsum and fluorite. Stalagmites and stalactites contain calcium carbonate.

General information

Discoveror: Sir Humphrey Davy
Date discovered: 1808
Discovered at: England
Meaning of name: From the Latin word "calx" meaning "lime"

Physical data

Standard state: solid at 298 K
Colour: silvery white
Density of solid at ambient temperature/kg m^-3: 1550
Molar volume/cm³: 26.20

Radii /pm

Atomic: 194
Covalent (single bond):
Pauling radius for the ion [Ca]^-: no data

Valence shell orbital radius maxima (R_max)

orbital	s	p	d	f
radius	183.9	no data	no data	no data

Electronegativities

Both values are quoted on the Pauling scale.

Pauling: 1.00
Allred Rochow: 1.04

Crystal Structure

structure: ccp (cubic close-packed)

The following CrystalMaker image represents the solid state structure. For most elements, the most stable allotrope is illustrated. Try WebElements version 2 for interactive virtual reality and CHIME images.

Temperatures (/K)

melting point: 1115
boiling point: 1757

Enthalpies /kJ mol^-1

fusion: 8.54
vaporization: 154.7

single bond enthalpies:

Ca-F	Ca-Cl	Ca-Br	Ca-I	Ca-Ca
550	429	402	326	46

Ionization enthalpies /kJ mol^-1

Number	Enthalpy
1st	589.8
2nd	1145.4
3rd	4912
4th	6474
5th	8144
6th	10496
7th	12320
8th	14207

Isotopes

This section gives some data for naturally occurring isotopes.

Nominal mass	Accurate mass	% natural abundance
40Ca	39.9625906 (13)	96.941 (13)
42Ca	41.9586176 (13)	0.647 (3)
43Ca	42.9587662 (13)	0.135 (3)
44Ca	43.9554806 (14)	2.086 (5)
46Ca	45.953689 (4)	0.004 (3)
48Ca	47.952533 (4)	0.187 (3)

Further Information

• Additional information about WebElements 1.2.2
• This is a licensed copy (here is the full list) of WebElements 1.2.2 and contains a subset of the material contained within the main version of WebElements (version 2)
• For further information please try WebElements version 2
• Sheffield Chemdex: perhaps the largest internet chemistry directory
• Sheffield Chemputer: interactive chemistry calculators on the WWW