Sodium amalgam (NaHg 2) has a different structure, with the mercury atoms forming hexagonal layers, and the sodium atoms a linear chain which fits into the holes in the hexagonal layers, but the potassium atom is too large for this structure to work in KHg 2.Īluminium can form an amalgam through a reaction with mercury. Phases K 5Hg 7 and KHg 11 are also known rubidium, strontium and barium undecamercurides are known and isostructural. The Hg-Hg distance is around 300 picometres, Hg-K around 358 pm. These amalgams are very sensitive to air and water, but can be worked with under dry nitrogen. KHg is a gold-coloured compound with a melting point of 178 ☌, and KHg 2 a silver-coloured compound with a melting point of 278 ☌. It is a binary solution (liquid-solid) of mercury and zinc.įor the alkali metals, amalgamation is exothermic, and distinct chemical forms can be identified, such as KHg and KHg 2. Formerly the zinc plates of dry batteries were amalgamated with a small amount of mercury to prevent deterioration in storage. It is the reducing agent in the Jones reductor, used in analytical chemistry.
Zinc amalgam finds use in organic synthesis (e.g., for the Clemmensen reduction).
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