continues to import a big part of its total consumption of the precious metal from some of the countries mentioned above. Since rhenium and its compounds are used in very small amounts, very little is known about their toxicity. So far, only a few rhenium compounds have been tested for toxicity, and these include rhenium trichloride and potassium perrhenate. Palladium And Platinum As Investment Commodities Palladium and platinum are two of nine metallic chemical elements considered "precious" for their rarity and high economic value. Like all the other precious metals, palladium and platinum have various industrial uses. But apart from these, both are also regarded as investment commodities. mol-1 * Electron Configuration: [Xe] 4f14 5d9 6s1 Physical: * Density (near room temperature): 21.45 g.cm-3 * Liquid Density (at melting point): 19.77 g.cm-3 * Melting Point: 1768.3 C, 3214.9 F, 2041.4 K * Boiling Point: 3825 C, 6917 F, 4098 K * Heat of Fusion: 22.17 kJ.mol-1 * Heat of Vaporization: 469 kJ. Gold - Ib/6; Au -> Au3+ + 3 e-; 1.498 V The second item appearing after the name of the metal (the three items are separated by semi-colons) represents the metal's reaction in water. In the pH diagram, the pH symbol is labeled on the horizontal axis to signify the -log function of the concentration of H+ ion. Ruthenium: Most Versatile Of The Platinum Group Metals Arranged by name alphabetically, ruthenium is the last of six metallic elements in the platinum group. This precious metal is characterized as being both polyvalent and versatile. In fact, it is known to be more versatile than any of the other five precious metals in the platinum group. Iridium: Iridium, when finely divided, can pose some hazards - it can ignite in air. Apart from this, accidental exposure to a radioisotope of iridium may cause poisoning by radiation, burns, and even death. Ruthenium: Three conditions may be associated with exposure to ruthenium: it can stain the skin; it may accumulate in bones; and it may increase the risk of cancer.