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Apart from 91 Y, 87 Y, and 90 Y, with half-lives of 58.51 days, 79.8 hours, and 64 hours, respectively; all other isotopes have half-lives of less than a day and most of less than an hour. [ 30 ] Yttrium isotopes with mass numbers at or below 88 decay mainly by positron emission (proton → neutron) to form strontium ( Z = 38) isotopes. [ 30 ]
Yttrium and pnictides can form compounds with the chemical formula YE (E = N, P, As, Sb). They can be hydrolyzed in humid air and emit volatile hydrides EH 3. Yttrium and carbon can form a variety of compounds, such as Y 2 C 3, [9] YC 2. [10] They can be made in several ways: 2 Y + 3 C → Y 2 C 3 Y 2 O 3 + 7 C → 2 YC 2 + 3 CO ↑
The Hill system (or Hill notation) is a system of writing empirical chemical formulae, molecular chemical formulae and components of a condensed formula such that the number of carbon atoms in a molecule is indicated first, the number of hydrogen atoms next, and then the number of all other chemical elements subsequently, in alphabetical order ...
atom A chemical element in its smallest form, made up of protons and neutrons within the nucleus and electrons circling the nucleus. An atom with protons, neutrons, and electrons labelled atomic mass The mass of an atom, typically expressed in daltons and nearly equivalent to the mass number multiplied by one dalton. atomic mass unit See dalton ...
Oxygen is the most abundant chemical element by mass in the Earth's biosphere, air, sea and land. Oxygen is the third most abundant chemical element in the universe, after hydrogen and helium. [68] About 0.9% of the Sun's mass is oxygen. [19]
Yttrium(III) nitrate is mainly used as a source of Y 3+ cations. It is a precursor of some yttrium-containing materials, such as Y 4 Al 2 O 9, [3] YBa 2 Cu 3 O 6.5+x [2] and yttrium-based metal-organic frameworks. [5] It can also be used as a catalyst in organic synthesis. [6]
A chemical element, often simply called an element, is a type of atom which has a specific number of protons in its atomic nucleus (i.e., a specific atomic number, or Z). [ 1 ] The definitive visualisation of all 118 elements is the periodic table of the elements , whose history along the principles of the periodic law was one of the founding ...
Its chemical formula, H 2 O, indicates that each of its molecules contains one oxygen and two hydrogen atoms, connected by covalent bonds. The hydrogen atoms are attached to the oxygen atom at an angle of 104.45°. [21] In liquid form, H 2 O is also called "water" at standard temperature and pressure.