Copper related properties and uses

Electronic structure and valence of copper

The atomic number of copper is 29, belonging to the IB family of the periodic table. The electronic layer is arranged as [Ar]3d104s1, which seems to be similar to potassium [Ar]4s1. However, since the shielding effect of d electrons is much weaker than that of p electrons, the first ionization potential of copper is 7.726Ev, and the second and third ionization potentials are about 10eV lower than potassium. This shows that copper is a metal that is not very vivid. It is between the base metal and the precious metal in the metal activity sequence, and it indicates that it may have multiple valence states.

The common habits of copper are +2 and +1. Cu(II) is a relatively stable valence state. A compound of Cu(III), such as CuF3, is formed under very strong oxidation conditions.

Copper compounds and coordination compounds

There are hundreds of copper compounds, among which the most industrial use value is copper sulfate, copper oxide, cuprous chloride, cuprous oxide and the like. Both Cu(II) and Cu(I) form many stable coordination compounds, in which Cu(II) complex and Cu(I) chlorination are important in hydrometallurgy.

When Cu(II) has a coordination number of 4, it is generally a planar square coordination, and when the coordination number is 6, it is a distorted octahedral configuration. The complexes formed by Cu(I) are mostly linear. A chelating ligand containing a nitrogen and oxygen donor such as barium salicylate, azoin, 8-hydroxyl and its substitutes and Cu2+ constitute a plurality of stable chelate compounds, and generally have a planar square structure. Many commercial copper extractants have been developed on the base of these ligands. The planar square structure constitutes the separate chemical base of copper.

Copper bio-use and hygiene standards

There are many organisms that contain copper-protease, and some of the gastropods in the gastropods of the gastropods, cephalopods, and crustaceans are ceruloplasmin. Plasma ceruloplasmin contains 8 copper atoms in human serum and has the function of catalyzing the oxidation of Fe2+. A person needs to consume 2.5 to 5 mg of copper per day, and 100 to 200 mg of copper in the body, mostly in the muscles.

Copper salts are highly toxic to lower organisms. The surface water limits the copper content to 0.1 mg/L, and the industrial wastewater discharge copper content should be less than 1 mg/L. WHO advocates drinking water with a copper content of 0.05 to 1.5 mg/L. The US regular workplace (time-weighted uniformity) threshold is: dust 1mg/m3, soot 0.2mg/m3.

Physical properties of copper

The crystal of copper is a face-centered cubic lattice with a density of 8.96t/m3, thermal conductivity of 394W/(m·K), a resistivity of 1.6730μΩ/cm at 20°C, and a temperature coefficient of resistivity of 1-100°C. It is 0.00681, the melting point is 1083 ° C, the latent heat of fusion is 212 kJ / kg, the specific heat capacity at 20 ° C is 384 J / (kg · ° C), the boiling point is 2595 ° C, the coefficient of linear expansion is 16.5 × 10 -6 ° C-1, tensile strength 23 ×104 kPa, modulus of elasticity (10.2 to 12) × 104 MPa, and modulus of rigidity 44,000 MPa.

Copper standards and uses

China's electrolytic copper fulfills the world GB466-82. The London Metal Trading Market (LME) Class A standard is often used in the world, and the standard for high purity cathode copper in China is similar.

Pure copper is used for wires and appliances. Copper constitutes a variety of alloys with primary industrial value. The alloy of copper and zinc is called brass, and the alloy of copper and tin is bronze, which is used for bearings, switches, heat exchangers, and the like. The alloy of copper and aluminum is called aluminum bronze, and the copper and bismuth alloys are called beryllium bronze. They have excellent mechanical properties and are used for mechanical and exterior parts. Copper and nickel form a white alloy, which is highly resistant to corrosion and is used in valves, pumps, and decoration. Copper and its alloys are primarily used in electric power, machinery, transportation, construction, electronics, and exteriors.