Amalgam (chemistry) but can be worked with under dry nitrogen. The Hg-Hg distance is around 300 picometres, Hg-K around 358 pm. Phases KHg and KHg are also known; rubidium, strontium and barium undecamercurides are known and isostructural. Sodium amalgam (NaHg) 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. Sodium amalgam is produced as a byproduct of the chloralkali process and used as an important reducing agent in organic and
Alchemy and chemistry in medieval Islam that have come down through the years were preserved as Arabic translations. In considering Islamic sciences as a distinct, local practice, it is important to define words such as "Arabic," "Islamic," "alchemy," and "chemistry." In order to gain a better grasp on the concepts discussed in this article, it is important to come to an understanding of what these terms mean historically. This may also help to clear up any misconceptions regarding the possible differences between alchemy and early chemistry in the context of medieval times. As A.I. Sabra writes in his article entitled, "Situating Arabic Science: Location versus Essence,"