(A) the basic physical properties of the basic physical properties of the noble metal elements listed in Table 1. Table 1  Basic physical properties of precious metals Physical properties ruthenium rhodium palladium silver osmium iridium platinum gold Atomic number 44 45 46 47 76 77 78 79 Atomic mass 101.07 102.9 106.4 107.9 190.2 192.2 195 196.7 Crystal structure Close hexagonal Face-centered cube Face-centered cube Face-centered cube Close hexagonal Face-centered cube Face-centered cube Face-centered cube Atomic radius /10 -10 m 1.25 1.25 1.28 1.34 1.26 1.27 1.3 1.34 Atomic volume //10 -30 m 8.3 8.5 8.9 10.21 8.5 8.6 9.12 10.1 Hardness ( diamond = 10 ) 6.5 　 5 2.5 7 6.5 4.5 2.5 Density / ( g / cm 3 ) 12.45 12.41 12.02 10.49 22.61 22.65 21.45 19.32 Melting point / °C 2427 1966 1550 961 3027 2454 1770 1063 Boiling point / °C 4119 3727 2900 2164 About 5020 4500 3824 2808 Specific heat capacity / ( J / g ) 0.231 0.247 0.245 0.234 0.129 0.129 0.131 0.129 Resistivity / [μΩ / ( cm · °C) 6.8 4.33 9.93 1.59 8.12 4.71 9.85 2.06 Temperature coefficient of resistance / (1/ ° C) 0.0042 0.00463 0.0038 0.0041 0.0042 0.00427 0.00393 0.004 The gold is golden yellow, the enamel is blue-gray, and the rest are silver-white. The processed dense metal surface has a strong ability to reflect light. Chongqing Huanyu Automobile Sales Company , https://www.cqhuanyuauto.com
As seen from the data listed in Table 1, the density, melting point and boiling point of the noble metal decrease with the order of Ru, Rh, Pd, Ag series and Os, Ir, Pt, Au series, and the machinability is improved. Among them, helium is the heaviest metal on the earth, which is 22.65 times the weight of water.
Gold and silver have the best processing properties. 1g gold can be drawn into filaments of 3km length. Platinum and processing properties are best in platinum group metals. Pure platinum can be cold rolled to 0.0025mm thick and 0.000127mm forged. The platinum foil is drawn into a filament with a diameter of only 0.001 mm; the platinum group metal has a strong adsorption gas characteristic, and the sponge-like platinum can absorb more than 114 times its volume of hydrogen, and can reach its own volume of 3,000. Times, é“‘ also has a similar nature. The conductivity of platinum and platinum-rhodium alloy wire, stable temperature coefficient of resistance and high melting point are important materials for accurate measurement of high temperature temperature and the benchmark for temperature correction.
Usually, precious metals and their alloys are machined into wires, sheets, tubes, plates and shaped materials of various specifications and processed into various components. It can also be used by plating, coating, coating, and the like.
Main physical, chemical and biochemical properties of precious metals (1)