Transition metal prevent d–d bonding, which again tends to differentiate them from the accepted transition metals. Mercury has a melting point of and is a liquid at room temperature. Transition metal In chemistry, the term transition metal (or transition element) has three possible meanings: English chemist Charles Bury (1890–1968) first used the word "transition" in this context in 1921, when he referred to a "transition series of elements" during the change of an inner layer of electrons (for example n=3 in the 4th row of the periodic table) from a stable group of 8 to one of 18, or from 18 to
Room temperature comfortable warmth is for normal, healthy adults who are appropriately dressed. For those with respiratory problems or allergies, they recommend no less than , and for the sick, disabled, very old or very young, a minimum of . Temperature ranges are defined as "room temperature" for certain products and processes in industry, science, and consumer goods. For instance, for the shipping and storage of pharmaceuticals, the United States Pharmacopeia-National Formulary (USP-NF) defines "controlled room temperature" as between , with excursions between allowed, provided the mean kinetic temperature does not exceed . The European Pharmacopoeia defines it as being simply ,