Praseodymium is a chemical element; it has symbol Pr and the atomic number 59. It is the third member of the lanthanide series and is considered one of the rare-earth metals. It is a soft, silvery, malleable and ductile metal, valued for its magnetic, electrical, chemical, and optical properties. It is too reactive to be found in native form, and pure praseodymium metal slowly develops a green oxide coating when exposed to air.
Kumyks are a Turkic ethnic group living in Dagestan, Chechnya and North Ossetia. They are the largest Turkic people in the North Caucasus.
Semyon Isaakovich Volfkovich was an outstanding Soviet chemist, inorganic chemist, technologist, Doctor of Chemical Sciences (1934), member of the Academy of Sciences of the Soviet Union. He was engaged in the technology of production of mineral fertilizers, studied the processes of electrothermal sublimation of phosphorus. He developed an industrial scheme for producing potassium salts from sylvinite and a new technology for producing concentrated phosphate fertilizers. He was the first in the USSR to conduct research on fluoride gases uilization, to study the processes of processing mirabilite into soda and ammonium sulfate. He studied the catalytic and other properties of aluminum-, boron-, iron-phosphates.
Yttrium phosphate, YPO4, is the phosphate salt of yttrium. It occurs in nature as minerals xenotime and weinschenkite.
Mishik Airazatovich Kazaryan was a Russian-Armenian physicist specialising in laser physics and optics, the winner of the State Prize of the USSR in the field of science and technology, foreign member of the Armenian National Academy of Sciences, member of the AM Prokhorov Academy of Engineering Sciences. Kazaryan was a creator of the brightest repetitively pulsed laser in the visible region of the spectrum.
Vladimir Isaakovich Minkin is a Russian chemist. Professor, Doctor of Chemical Sciences.
Praseodymium(III) fluoride is an inorganic compound with the formula PrF3, being the most stable fluoride of praseodymium.
Neptunium (IV) oxalate is an inorganic compound, a salt of neptunium and oxalic acid with the chemical formula Np(C2O4)2. The compound is slightly soluble in water, forms crystalline hydrates—green crystals.
Petersburg Institute of St. Helena is a closed women's educational institution of the Russian Empire, part of the department of institutions of Empress Maria, which existed from 1821 to 1918 in St. Petersburg.
Neodymium(III) hydride is an inorganic compound composed of neodymium and hydrogen with a chemical formula NdH3. In this compound, the neodymium atom is in the +3 oxidation state and the hydrogen atoms are -1. It is highly reactive.
Ytterbium(III) acetate is an inorganic salt of ytterbium and acetic acid, with a chemical formula of Yb(CH3COO)3. It has colorless crystals that are soluble in water and can form hydrates.
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).
Gadolinium acetate is the acetate salt of the lanthanide element gadolinium, with the chemical formula Gd(CH3COO)3. It is a colorless crystal that is soluble in water and can form a hydrate. Its tetrahydrate has ground state ferromagnetism.
Praseodymium bismuthide is a binary inorganic compound of praseodymium and bismuth with the chemical formula of PrBi. It forms crystals.
Praseodymium arsenide is a binary inorganic compound of praseodymium and arsenic with the formula PrAs.
Praseodymium bromide is an inorganic compound with the chemical formula Pr(BrO3)3. It is soluble in water and can form the dihydrate, tetrahydrate and nonahydrate. The nonahydrate melts in its own crystal water at 56.5 °C and completely loses its crystal water at 130 °C. It can be produced by the reaction of barium bromate and praseodymium sulfate.
Praseodymium(III) molybdate is a salt of praseodymium and molybdic acid with the chemical formula Pr2(MoO4)3. It forms crystals that are insoluble in water.
Praseodymium tetraboride is a binary inorganic compound of praseodymium and boron with the chemical formula PrB4.
Lanthanide compounds are compounds formed by the 15 elements classed as lanthanides. The lanthanides are generally trivalent, although some, such as cerium and europium, are capable of forming compounds in other oxidation states.
