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It is the least dense and has the lowest melting point of the platinum group metals. It is soft and ductile when annealed and is greatly increased in strength and hardness when cold-worked. Palladium dissolves slowly in concentrated nitric acid, in hot, concentrated sulfuric acid, and when finely ground, in hydrochloric acid. [11]
The Gmelin rare earths handbook lists 1522 °C and 1550 °C as two melting points given in the literature, the most recent reference [Handbook on the chemistry and physics of rare earths, vol.12 (1989)] is given with 1529 °C.
Palladium oxide is prepared by heating palladium sponge metal in oxygen at 350 °C. 2 Pd + O 2 → 2 PdO. The oxide is obtained as a black powder. The oxide also may be prepared specially for catalytic use by heating variously a mixture of palladium(II) chloride and potassium nitrate, 2 PdCl 2 + 4 KNO 3 → 2 PdO + 4 KCl + 4 NO 2 + O 2 ...
This list is sorted by boiling point of gases in ascending order, but can be sorted on different values. "sub" and "triple" refer to the sublimation point and the triple point, which are given in the case of a substance that sublimes at 1 atm; "dec" refers to decomposition. "~" means approximately. Blue type items have an article available by ...
Naturally occurring platinum and platinum-rich alloys were known by pre-Columbian Americans for many years. [5] However, even though the metal was used by pre-Columbian peoples, the first European reference to platinum appears in 1557 in the writings of the Italian humanist Julius Caesar Scaliger (1484–1558) as a description of a mysterious metal found in Central American mines between ...
Palladium acetate, in trimeric form, can be prepared by treating palladium sponge with a mixture of acetic acid and nitric acid. An excess of palladium sponge metal or nitrogen gas flow are required to prevent contamination by the mixed nitrito-acetate (Pd 3 (OAc) 5 NO 2). [6] [7] Pd + 4 HNO 3 → Pd(NO 3) 2 + 2 NO 2 + 2 H 2 O
The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state from solid to liquid. At the melting point the solid and liquid phase exist in equilibrium. The melting point of a substance depends on pressure and is usually specified at a standard pressure such as 1 atmosphere or 100 kPa.
The hydrogen atoms occupy interstitial sites in palladium hydride. The H–H bond in H 2 is cleaved. The ratio in which H is absorbed on Pd is defined by = [] [].When Pd is brought into a H 2 environment with a pressure of 1 atm, the resulting concentration of H reaches x ≈ 0.7.