Copper
Main page |
| Other names/abbreviations: | Cu |
| Element no: | 29 |
| Element group: | 11 (IUPAC) I B (American labelling) I B (European labelling) Coinage metals |
| Element type: | Transition metals |
| CAS-Number: | 7440-50-8 |
| EINECS-Number: | 231-159-6 |
Chemical properties
Reaction of copper with acidsCopper metal dissolves in hot concentrated sulphuric acid forming Cu(II) ions and hydrogen, H2. In water, Cu(II) is present as the complex ion [Cu(H2O)6]2+.
Cu (s) + H2SO4 (aq)
Cu2+ (aq) + SO42- (aq) + H2 (g)Copper metal also dissolves in dilute or concentrated nitric acid, HNO3.
3 Cu (s) + 2 NO3- (aq) + 8 H+ (aq)
3 Cu2+ (aq) + 2 NO (g) + 4 H2O (l)Reaction of copper with air
Copper metal is stable in air under normal conditions. When heated until red hot, copper metal and oxygen react to form Cu2O.
4 Cu (s) + O2 (g)
2 Cu2O (s)Reaction of copper with ammonia
Copper(II)ions are precipitated by ammonia:
[Cu(H2O)6]2+ (aq) [blue] + 2 NH3 (aq)
[Cu(OH)2(H2O)4] (s) [blue] + 2 NH4+ (aq)The precipitate dissolves in excess amonia.
[Cu(OH)2(H2O)4] (s) + 4 NH3(aq)
[Cu(NH3)4]2+ (aq) [royal blue] + 2 H2O (l) + 2 OH- (aq)Reaction of copper with carbonate
Cu(II) is precipitated by carbonate:
[Cu(H2O)6]2+ (aq) [blue] + CO32- (aq)
CuCO3 (s) [blue] + 6 H2O (l)Reaction of copper with halogens
Metallic copper metal reacts with the halogens forming corresponding dihalides.
Cu (s) + F2 (g)
CuF2 (s) [white]Cu (s) + Cl2 (g)
CuCl2 (s) [yellow-brown]Cu (s) + Br2 (g)
CuBr2 (s) [black]Cu(II) forms yellow complexes with 4 Cl-. Complexes with fewer chloride ions exist. These are light blue to bluish green:
[Cu(H2O)6]2+ (aq) [blue, octahedral] + 4 Cl- (aq)
[CuCl4]2- (aq) [yellow, tetrahedral] + 6 H2O (l)Cu(II) is reduced to Cu(I) and precipitated by I-:
2[Cu(H2O)6]2+ (aq) [blue, octahedral]) + 4 I- (aq)
2 CuI (s) [white] + I2 (aq) + 6 H2O (l)Reaction of copper with hydroxide
Cu(II) is precipitated by hydroxide. Concentrated hydroxide will dissolve the precipitate:
[Cu(H2O)6]2+ (aq) [blue] + 2 OH- (aq)
Cu(OH)2(H2O)4 (s) [light blue] + 2 H2O (l)2 Cu(OH)2 (s) [light blue] + 3 OH- (aq)
[Cu(OH)4]2- (aq) [blue] + [Cu(OH)3]- (aq) [blue]Reaction of copper with metal/metal ions
Copper is oxidized by Hg(II)
Hg2+ (aq) + Cu (s)
Hg (l) + Cu2+ (aq)Copper(II) is reduced by iron and zinc
3 Cu2+ (aq) + 2 Fe (s)
3 Cu (s) + 2 Fe3+ (aq)Cu2+ (aq) + Zn (s)
3 Cu (s) + Zn2+ (aq)Reaction of copper with sulfide
Copper(II) is precipitated by sulfide in 0.4 M hydrochloric acid
Cu2+ (aq) + H2S (aq)
CuS (s) + 2 H+ (aq)Quantitative analysis
Method 3500-Cu C Inductively Coupled Plasma Method [1]. A portion of the sample is digested in a combination of acids. The digest is aspirated into an 8,000 K argon plasma where resulting light emission is quantified for 30 elements simultaneously.Method limit of detection in water = 0.002 mg/L
Method limit of detection in soil = 1.00 mg/kg
Safety
Symbol: -R-phrases: -
S-phrases: -
Physical properties
Appearance | ||
| Physical state @ 20°C: | Solid | |
| Color: | Light pink to copper red. Weathered specimens tarnished green [4] | |
| Luster: | Metallic [4] | |
| Transparency: | Opaque [4] | |
| Streak: | Red [4] | |
| Odor: | Odourless [5] | |
Bulk properties | ||
| Molecular weight (g/mol): | 63.546 [2] | |
| Melting point (°C): | 1083 [2] | |
| Boiling point (°C): | 2570 [2] | |
| Density (g/cm3): | 8.95 (20 °C) [2] | |
| Molar volume (cm3): | 7.11 (20 °C) [3] | |
| Elastic properties: Young's modulus (GPa): Rigidity modulus (GPa): Bulk modulus (GPa): Poisson ratio: |
112-131 [3] 46-48 [3] 138 [3] 0.31-0.35 [3] | |
| Hardness: Mineral hardness: |
2.5 [4] | |
Thermodynamic properties | ||
| ΔH°atomization (KJ/mol): | 337 [2] | |
| ΔfH°gas (KJ/mol): | 337.4 (monoatomic) [6] 484.2 (Cu2) [6] | |
| ΔfH°solid (KJ/mol): | 0.0 (monoatomic) [6] | |
| ΔH°fusion (KJ/mol): | 13.26 [6] | |
| ΔH°vaporization (KJ/mol): | 307±6 [2] | |
| S°gas (J/K·mol): | 166.4 (monoatomic) [6] 241.6 (Cu2) [6] | |
| S°solid (J/K·mol): | 33.2 (monoatomic) [6] | |
| ΔfG°gas (kJ/mol): | 297.7 (monoatomic) [6] 431.9 (Cu2) [6] | |
| Cp (gas) (J/K·mol): | 20.8 (monoatomic, 25 °C) [6] 36.6 (Cu2, 25 °C) [6] | |
| Cp (solid) (J/K·mol): | 24.3364 (20 °C) [3] 24.440 (monoatomic, 25 °C) [6] 24.6024 (100 °C) [3] 25.4801 (200 °C) [3] 26.9961 (500 °C) [3] 29.5229 (1000 °C) [3] | |
| Coeff. of linear thermal expansion (106 K-1): | 17.0 (20 °C) [3] 16.5 (monoatomic, 25 °C) [6] 17.1 (100 °C) [3] 17.2 (200 °C) [3] 18.3 (500 °C) [3] 20.3 (1000 °C) [3] | |
Crystal structure | ||
| Crystal type: | Face centered cubic [3] | |
| Cleavage | None [4] | |
| Fracture | Jagged [4] | |
Electronic properties | ||
 |
Electron configuration: | 1s2-2s2-2p6-3s2-3p6-3d10-4s1 |
| Ionic radius (Å): | Cu(III): 0.54 (6-coordinate) [2] Cu(II): 0.73 (6-coordinate) [2] Cu(I): 0.77 (6-coordinate) [2] | |
Conductivity | ||
| Electrical resisitvity (μΩ·cm): | 1.69 (20 °C) [3] 1.58 (25 °C) [3] 2.93 (200 °C) [3] 4.60 (597 °C) [3] 8.10 (977 °C) [3] | |
| Thermal (W/m·K): | 394 (20 °C) [3] 401 (27 °C) [6] 391 (100 °C) [3] 389 (200 °C) [3] | |
Occurrence, isolation & synthesis
Primary hydrothermal copper is mainly related to basic igneous rocks and as a product of supergene cementation. Otherwise copper is found in various minerals and metals [4].Notable occurrences
Keweenaw Peninsular, Lake Superior, USA (largest deposit of primaru copper); Tsumeb, Namibia and Chessy, France, Ural mountains, Russia [4]
Associated minerals
Silver, calcite, malachite, chalcosite, bornite and other secondary copper minerals [4].
References
1: Standard Methods for the Analysis of Water and Wastewater, APHA, 1992, 18th edition2: Greenwood,N.N., Earnshaw,A. Chemistry of the elements
2nd edition (1997) Edited by Greenwood,N.N., Earnshaw,A. pp. 1-1340, Butterworth-Heinemann. Oxford. Great Britain
3: Buch,A. Pure Metals Properties. A Scientific-Technical Handbook
1st edition (1999) Edited by Buch,A. pp. 1-306, ASM International and Freund Publishing House Ltd. Ohio. USA
4: Korbel,P., Novák,M. The Complete Encyclopedia of Minerals
1st edition (1999) pp1-296, Chartwell Books, Inc. New Jersey, USA
5: Merck. ChemDAT The Merck Chemical Database Ver. 1.1.5
6: CRC Handbook of Chemistry and Physics
75th edition (1994) Edited by Lide,D.R. , CRC Press Inc. Boca Raton, USA
© Michael Pilgaard
Created: September 26, 2006
Last update: October 10, 2006