Scandium is a chemical element; it has symbol Sc and atomic number 21. It is a silvery-white metallic d-block element. Historically, it has been classified as a rare-earth element, together with yttrium and the lanthanides. It was discovered in 1879 by spectral analysis of the minerals euxenite and gadolinite from Scandinavia.
Phosphine (IUPAC name: phosphane) is a colorless, flammable, highly toxic compound with the chemical formula PH3, classed as a pnictogen hydride. Pure phosphine is odorless, but technical grade samples have a highly unpleasant odor like rotting fish, due to the presence of substituted phosphine and diphosphane (P2H4). With traces of P2H4 present, PH3 is spontaneously flammable in air (pyrophoric), burning with a luminous flame. Phosphine is a highly toxic respiratory poison, and is immediately dangerous to life or health at 50 ppm. Phosphine has a trigonal pyramidal structure.
In chemistry, a phosphide is a compound containing the P3− ion or its equivalent. Many different phosphides are known, with widely differing structures. Most commonly encountered on the binary phosphides, i.e. those materials consisting only of phosphorus and a less electronegative element. Numerous are polyphosphides, which are solids consisting of anionic chains or clusters of phosphorus. Phosphides are known with the majority of less electronegative elements with the exception of Hg, Pb, Sb, Bi, Te, and Po. Finally, some phosphides are molecular.
Hypophosphorous acid (HPA), or phosphinic acid, is a phosphorus oxyacid and a powerful reducing agent with molecular formula H3PO2. It is a colorless low-melting compound, which is soluble in water, dioxane and alcohols. The formula for this acid is generally written H3PO2, but a more descriptive presentation is HOP(O)H2, which highlights its monoprotic character. Salts derived from this acid are called hypophosphites.
Iron phosphide is a chemical compound of iron and phosphorus, with a formula of FeP. Its physical appearance is grey, hexagonal needles.
Scandium compounds are compounds containing the element scandium. The chemistry of scandium is almost completely dominated by the trivalent ion, Sc3+, due to its electron configuration, [Ar] 3d14s2. The radii of M3+ ions in the table below indicate that the chemical properties of scandium ions have more in common with yttrium ions than with aluminium ions. In part because of this similarity, scandium is often classified as a lanthanide-like element.
Oxyphosphides are chemical compounds formally containing the group PO, with one phosphorus and one oxygen atom. The phosphorus and oxygen are not bound together as in phosphates or phosphine oxides, instead they are bound separately to the cations (metals), and could be considered as a mixed phosphide-oxide compound. So a compound with OmPn requires cations to balance a negative charge of 2m+3n. The cations will have charges of +2 or +3. The trications are often rare earth elements or actinides. They are in the category of oxy-pnictide compounds.
Yttrium phosphide is an inorganic compound of yttrium and phosphorus with the chemical formula YP. The compound may be also classified as yttrium(III) phosphide.
Phosphide silicides or silicide phosphides or silicophosphides are compounds containing anions composed of silicide (Si4−) and phosphide (P3−). They can be considered as mixed anion compounds. They are distinct from the phosphidosilicates, which have the phosphorus bonded to the silicon. Related compounds include the phosphide carbides, germanide phosphides, nitride silicides, and antimonide silicides.
Lithium phosphide is an inorganic compound of lithium and phosphorus with the chemical formula Li
3P. This dark colored compound is formally the Li+ salt of P3-. It is a hazardous to handle because of its high reactivity toward air.
Praseodymium monophosphide is an inorganic compound of praseodymium and phosphorus with the chemical formula PrP. The compound forms crystals.
Europium phosphide is an inorganic compound of europium and phosphorus with the chemical formula EuP. Other phosphides are also known.
Samarium(III) phosphide is an inorganic compound of samarium and phosphorus with the chemical formula SmP.
Lanthanum phosphide is an inorganic compound of lanthanum and phosphorus with the chemical formula LaP.
Thulium phosphide is an inorganic compound of thulium and phosphorus with the chemical formula TmP.
Terbium phosphide is an inorganic compound of terbium and phosphorus with the chemical formula TbP.
Gadolinium phosphide is an inorganic compound of gadolinium and phosphorus with the chemical formula GdP.
Phosphide iodides or iodide phosphides are compounds containing anions composed of iodide (I−) and phosphide (P3−). They can be considered as mixed anion compounds. They are in the category of pnictidehalides. Related compounds include the phosphide chlorides, arsenide iodides antimonide iodides and phosphide bromides.
Terbium compounds are compounds formed by the lanthanide metal terbium (Tb). Terbium generally exhibits the +3 oxidation state in these compounds, such as in TbCl3, Tb(NO3)3 and Tb(CH3COO)3. Compounds with terbium in the +4 oxidation state are also known, such as TbO2 and BaTbF6. Terbium can also form compounds in the 0, +1 and +2 oxidation states.
Ytterbium compounds are chemical compounds that contain the element ytterbium (Yb). The chemical behavior of ytterbium is similar to that of the rest of the lanthanides. Most ytterbium compounds are found in the +3 oxidation state, and its salts in this oxidation state are nearly colorless. Like europium, samarium, and thulium, the trihalides of ytterbium can be reduced to the dihalides by hydrogen, zinc dust, or by the addition of metallic ytterbium. The +2 oxidation state occurs only in solid compounds and reacts in some ways similarly to the alkaline earth metal compounds; for example, ytterbium(II) oxide (YbO) shows the same structure as calcium oxide (CaO).
