Fluorine named the acidic product "fluss-spats-syran" (fluorspar acid). In 1810, the French physicist André-Marie Ampère suggested that hydrogen and an element analogous to chlorine constituted hydrofluoric acid. Sir Humphry Davy proposed that this then-unknown substance be named "fluorine" from fluoric acid and the "-ine" suffix of other halogens. This word, with modifications, is used in most European languages; Greek, Russian, and some others (following Ampère's suggestion) use the name "ftor" or derivatives, from the Greek φθόριος ("phthorios", destructive). The New Latin name "fluorum" gave the element its current symbol F; Fl was used in early papers. Initial studies on fluorine were
Copper and halides. Both cuprous and cupric oxides are known. Among the numerous copper sulfides, important examples include copper(I) sulfide and copper(II) sulfide. Cuprous halides (with chlorine, bromine, and iodine) are known, as are cupric halides with fluorine, chlorine, and bromine. Attempts to prepare copper(II) iodide yield only cuprous iodide and iodine. Copper forms coordination complexes with ligands. In aqueous solution, copper(II) exists as [Cu(HO)]. This complex exhibits the fastest water exchange rate (speed of water ligands attaching and detaching) for any transition metal aquo complex. Adding aqueous sodium hydroxide causes the precipitation of light blue solid copper(II) hydroxide. A simplified