Monazite is a primarily reddish-brown phosphate mineral that contains rare-earth elements. Due to variability in composition, monazite is considered a group of minerals. The most common species of the group is monazite-(Ce), that is, the cerium-dominant member of the group. It occurs usually in small isolated crystals. It has a hardness of 5.0 to 5.5 on the Mohs scale of mineral hardness and is relatively dense, about 4.6 to 5.7 g/cm3. There are five different most common species of monazite, depending on the relative amounts of the rare earth elements in the mineral:
A polyphosphate is a salt or ester of polymeric oxyanions formed from tetrahedral PO4 (phosphate) structural units linked together by sharing oxygen atoms. Polyphosphates can adopt linear or a cyclic (also called, ring) structures. In biology, the polyphosphate esters ADP and ATP are involved in energy storage. A variety of polyphosphates find application in mineral sequestration in municipal waters, generally being present at 1 to 5 ppm. GTP, CTP, and UTP are also nucleotides important in the protein synthesis, lipid synthesis, and carbohydrate metabolism, respectively. Polyphosphates are also used as food additives, marked E452.
Praseodymium(III) chloride is the inorganic compound with the formula PrCl3. Like other lanthanide trichlorides, it exists both in the anhydrous and hydrated forms. It is a blue-green solid that rapidly absorbs water on exposure to moist air to form a light green heptahydrate.
In chemistry, a phosphoric acid, in the general sense, is a phosphorus oxoacid in which each phosphorus (P) atom is in the oxidation state +5, and is bonded to four oxygen (O) atoms, one of them through a double bond, arranged as the corners of a tetrahedron. Two or more of these PO4 tetrahedra may be connected by shared single-bonded oxygens, forming linear or branched chains, cycles, or more complex structures. The single-bonded oxygen atoms that are not shared are completed with acidic hydrogen atoms. The general formula of a phosphoric acid is Hn+2−2xPnO3n+1−x, where n is the number of phosphorus atoms and x is the number of fundamental cycles in the molecule's structure, between 0 and n + 2/2.
Tricalcium phosphate (sometimes abbreviated TCP), more commonly known as Calcium phosphate, is a calcium salt of phosphoric acid with the chemical formula Ca3(PO4)2. It is also known as tribasic calcium phosphate and bone phosphate of lime (BPL). It is a white solid of low solubility. Most commercial samples of "tricalcium phosphate" are in fact hydroxyapatite.
Calcium pyrophosphate (Ca2P2O7) is a chemical compound, an insoluble calcium salt containing the pyrophosphate anion. There are a number of forms reported: an anhydrous form, a dihydrate, Ca2P2O7·2H2O and a tetrahydrate, Ca2P2O7·4H2O. Deposition of dihydrate crystals in cartilage are responsible for the severe joint pain in cases of calcium pyrophosphate deposition disease (pseudo gout) whose symptoms are similar to those of gout. Ca2P2O7 is commonly used as a mild abrasive agent in toothpastes, because of its insolubility and nonreactivity toward fluoride.
Zinc pyrophosphate (Zn2P2O7) is an ionic inorganic chemical compound composed of Zn2+ cations and pyrophosphate anions.
Chromium(III) phosphate describes inorganic compounds with the chemical formula CrPO4·(H2O)n, where n = 0, 4, or 6. All are deeply colored solids. Anhydrous CrPO4 is green. The hexahydrate CrPO4·6H2O is violet.
Vanadium phosphates are inorganic compounds with the formula VOxPO4 as well related hydrates with the formula VOxPO4(H2O)n. Some of these compounds are used commercially as catalysts for oxidation reactions.
Iron(III) pyrophosphate is an inorganic chemical compound with the formula Fe4(P2O7)3.
Nickel is one of the metals that can form Tutton's salts. The singly charged ion can be any of the full range of potassium, rubidium, cesium, ammonium (), or thallium. As a mineral the ammonium nickel salt, (NH4)2Ni(SO4)2 · 6 H2O, can be called nickelboussingaultite. With sodium, the double sulfate is nickelblödite Na2Ni(SO4)2 · 4 H2O from the blödite family. Nickel can be substituted by other divalent metals of similar sized to make mixtures that crystallise in the same form.
Neodymium(III) acetate is an inorganic salt composed of a neodymium atom trication and three acetate groups as anions where neodymium exhibits the +3 oxidation state. It has a chemical formula of Nd(CH3COO)3 although it can be informally referred to as NdAc because Ac is an informal symbol for acetate. It commonly occurs as a light purple powder.
Neodymium compounds are compounds formed by the lanthanide metal neodymium (Nd). In these compounds, neodymium generally exhibits the +3 oxidation state, such as NdCl3, Nd2(SO4)3 and Nd(CH3COO)3. Compounds with neodymium in the +2 oxidation state are also known, such as NdCl2 and NdI2. Some neodymium compounds have colors that vary based upon the type of lighting.
Neodymium(II) iodide or neodymium diiodide is an inorganic salt of iodine and neodymium the formula NdI2. Neodymium uses the +2 oxidation state in the compound.
The phosphate sulfates are mixed anion compounds containing both phosphate and sulfate ions. Related compounds include the arsenate sulfates, phosphate selenates, and arsenate selenates.
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.
Promethium(III) phosphate is an inorganic compound, a salt of promethium and phosphate, with the chemical formula of PmPO4. It is radioactive. Its hydrate can be obtained by precipitation of soluble promethium salt and diammonium hydrogen phosphate at pH 3~4 (or obtained by hydrothermal reaction ), and the hydrate can be obtained by burning at 960 °C to obtain the anhydrous form. Its standard enthalpy of formation is −464 kcal/mol.
Manganese(III) phosphate is an inorganic chemical compound of manganese with the formula MnPO4. It is a hygroscopic purple solid that absorbs moisture to form the pale-green monohydrate, though the anhydrous and monohydrate forms are typically each synthesized by separate methods.
Transition metal phosphate complexes are coordination complexes with one or more phosphate ligands. Phosphate binds to metals through one, two, three, or all four oxygen atoms. The bidentate coordination mode is common. The second and third pKa's of phosphoric acid, pKa2 and pKa3, are 7.2 and 12.37, respectively. It follows that HPO2−4 and PO3−4 are sufficiently basic to serve as ligands. The examples below confirm this expectation. Molecular metal phosphate complexes have no or few applications.
Praseodymium phosphate is an inorganic compound with the chemical formula PrPO4. Its hemihydrate can be obtained by reacting praseodymium chloride and phosphoric acid. It can also be produced by reacting silicon pyrophosphate (SiP2O7) and praseodymium(III,IV) oxide (Pr6O11) at 1200 °C. It reacts with sodium fluoride to obtain Na2PrF2(PO4).
