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Barium, 56Ba |
| Barium |
|---|
| Pronunciation | (BAIR-ee-əm) |
|---|
| Appearance | sillery gray; wi a fauch yellae tint[1] |
|---|
| Standard atomic weight Ar, std(Ba) | 7002137327000000000♠137.327(7)[2] |
|---|
| Barium in the periodic cairt |
|---|
|
|
| Atomic nummer (Z) | 56 |
|---|
| Group | group 2 (alkaline yird metals) |
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| Period | period 6 |
|---|
| Block | s-block |
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| Element category | Alkaline earth metal |
|---|
| Electron confeeguration | [Xe] 6s2 |
|---|
| Electrons per shell | 2, 8, 18, 18, 8, 2 |
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| Pheesical properties |
|---|
| Phase at STP | solit |
|---|
| Meltin pynt | 1000 K (727 °C, 1341 °F) |
|---|
| Bylin pynt | 2118 K (1845 °C, 3353 °F) |
|---|
| Density (near r.t.) | 3.51 g/cm3 |
|---|
| when liquid (at m.p.) | 3.338 g/cm3 |
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| Heat o fusion | 7.12 kJ/mol |
|---|
| Heat o vapourisation | 142 kJ/mol |
|---|
| Molar heat capacity | 28.07 J/(mol·K) |
|---|
Vapour pressur
| P (Pa)
|
1
|
10
|
100
|
1 k
|
10 k
|
100 k
|
| at T (K)
|
911
|
1038
|
1185
|
1388
|
1686
|
2170
|
|
| Atomic properties |
|---|
| Oxidation states | +1, +2 strangly basic |
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| Electronegativity | Pauling scale: 0.89 |
|---|
| Ionisation energies | - 1st: 502.9 kJ/mol
- 2nd: 965.2 kJ/mol
- 3rd: 3600 kJ/mol
-
|
|---|
| Atomic radius | empirical: 222 pm |
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| Covalent radius | 215±11 pm |
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| Van der Waals radius | 268 pm |
|---|
 Colour lines in a spectral rangeSpectral lines o barium |
| Ither properties |
|---|
| Naitural occurrence | primordial |
|---|
| Creestal structur | body-centred cubic (bcc) |
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| Speed o soond thin rod | 1620 m/s (at 20 °C) |
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| Thermal expansion | 20.6 µm/(m·K) (at 25 °C) |
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| Thermal conductivity | 18.4 W/(m·K) |
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| Electrical resistivity | 332 nΩ·m (at 20 °C) |
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| Magnetic orderin | paramagnetic[3] |
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| Young's modulus | 13 GPa |
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| Shear modulus | 4.9 GPa |
|---|
| Bulk modulus | 9.6 GPa |
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| Mohs haurdness | 1.25 |
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| CAS Nummer | 7440-39-3 |
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| History |
|---|
| Diskivery | Carl Wilhelm Scheele (1772) |
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| First isolation | Humphry Davy (1808) |
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| Main isotopes o barium |
|---|
|
|
| Decay modes in parentheses is predictit, but hisnae yet been observed |
| | references |
| style="text-align:left"|
|
|
|
in
|
calc from C
|
diff
|
report
|
ref
|
| C
|
727
|
—
|
—
|
|
|
| K
|
1000
|
1000
|
0
|
|
|
| F
|
1341
|
1341
|
0
|
|
|
| WD
|
727 !727 Celsius 
|
|
|
|
| input
|
C: 727, K: 1000, F: 1341
|
| comment
|
|
| style="text-align:left"|
|
|
|
in
|
calc from C
|
diff
|
report
|
ref
|
| C
|
1845
|
—
|
—
|
|
|
| K
|
2118
|
2118
|
0
|
|
|
| F
|
3353
|
3353
|
0
|
|
|
| WD
|
1897 !1897 Celsius
|
|
|
|
| input
|
C: 1845, K: 2118, F: 3353
|
| comment
|
|
References
Thir references will appear in the airticle, but this list appears anerly on this page.
- ↑ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth–Heinemann. p. 112. ISBN 0080379419.
- ↑ Meija, Juris; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry. 88 (3): 265–91. doi:10.1515/pac-2015-0305.
- ↑ Magnetic susceptibility of the elements and inorganic compounds, in Lide, D. R., ed. (2005). CRC Handbook of Chemistry and Physics (86th ed.). Boca Raton (FL): CRC Press. ISBN 0-8493-0486-5.
- ↑ Standard Atomic Weights 2013. Commission on Isotopic Abundances and Atomic Weights
