Deuterium, atomic symbol

Hydrogen The first chemical element in the periodic table. It has the atomic symbol H, atomic number 1, and atomic weight 1. It exists, under normal conditions, as a colorless, odorless, tasteless, diatomic gas. Hydrogen ions are protons. Besides the common HI isotope, hydrogen exists as the stable isotope deuterium and the unstable, radioactive isotope tritium. [NIH]... 

Note that of all the isotopes of all the elements, only those of hydrogen, and H, also have specific atomic symbols, D and T, with associated names deuterium and tritium. 

Isotope Isotopic specification is indicated by prefixing the atomic symbol with a number equal to the integral isotopic mass—for example, [2H] for deuterium and [13C] for carbon-13. 

Structures that are achiral but which can be made chiral by substitution are said to be prochiral. In the example of butane, replacement of one of the hydrogen atoms on C2 by a deuterium atom as shown on the top of Figure 2.42 gives (R)-2-deuteriobutane, (K)-104. Therefore, that hydrogen is said to be the pro-(R) substituent and is indicated by the symbol Replacement of... 

The C-D bond formed is stronger than the C-H bond by about 1 v2 kcal/mol, so that (ke-i)H/(ke-l)D term is expected to be smaller than unity, where the symbol (ke i)p represents the rate constant for addition of deuterium atom, etc. Based on the kinetic isotope effect at 25°C reported by Daby et al., (10) (ke-i)H/ ( e-l)D 1000 K is estimated at 0.91. 

In naming compounds, the presence of deuterium is shown by the symbol "d" and the number of deuterium atoms is shown by a subscript following it. In addition to acetone-dg, more than 225 deuterium-labeled compounds are available commercially in isotopic enrichments of up to 99.8 atom % D. Among these are the following ... 

Hydrogen occurs naturally in three isotopes. The most common ( H) accounting for more than 99.98% of hydrogen in water, consists of only a single proton in its nucleus. A second, stable isotope, deuterium (chemical symbol D or H), has an additional neutron. Deuterium oxide, D2O, is also known as heavy water because of its higher density. It is used in nuclear reactors as a neutron moderator. The third isotope, tritium, has 1 proton and 2 neutrons, and is radioactive, decaying with a half-life of 4500 days. T2O exists in nature only in minute quantities, being produced primarily via cosmic ray-induced nuclear reactions in the atmosphere. Water with one deuterium atom HDO occurs... 

Usually all the isotopes of an element share the same name and atomic symbol. The exception is hydrogen. Isotope fH is called deuterium (symbol D), and fH is tritium (T). 

The italicized symbols d- (for deuterium) and t- (for tritium) are placed after the formula and connected to it by a hyphen. The number of deuterium or tritium atoms is indicated by a subscript to the symbol. 

Deuterium [16873-17-9] (symbol or D) occurs ia nature in all hydrogen-containing compounds to the extent of about 0.0145 atom %. Small but real... 

Examples of isotopes are abundant. The major form of hydrogen is represented as H (or H-1), with one proton H, known as the isotope deuterium or heavy hydrogen, consists of one proton and one neutron (thus an amu of 2) and is the isotope of hydrogen called tritium with an amu of 3. Carbon-12 ( C or C-12) is the most abundant form of carbon, though carbon has several isotopes. One is the C isotope, a radioactive isotope of carbon that is used as a tracer and to determine dates of organic artifacts. Uranium-238 is the radioactive isotope (Note The atomic number is placed as a subscript prefix to the element s symbol—for example, —and the atomic mass number can be written either as a dash and number fol-... 

An isotope of hydrogen having a nucleus (referred to as the deutron) consisting of one proton and one neutron. Deuterium is a stable isotope (symbolized by or D) having an atomic weight of 2.0140 amu and a natural abundance of 0.015% relative to all hydrogen isotopes. 

Symbol H atomic number 1 atomic weight 1.0079 the lightest of all the chemical elements the first element in the Periodic Table Group lA (group 1) nonmetallic gaseous element occurs as H2, a diatomic molecule electron configuration Ish valences -i-l and-1 three isotopes H-1 or protium (99.9844%), H-2 or deuterium (0.0156%), H-3 or tritium (radioactive, ty, =12.4 yr., in traces... 

A given isotope is represented by showing its element symbol with mass number as a left superscript and atomic number as a left subscript. Thus, protium is represented as jH, deuterium as jH, and tritium as fH. Similarly, the two naturally... 

The isotopic abundance of deuterium in the three hydrogen atoms of the hydrogen ion differs from that in the water. The fractionation parameter involved is designated by the symbol l, i.e. 

Hydrogen-2 is called deuterium and is often represented by the symbol D. Hydrogen-3 is known as tritium and is often represented by the symbol T. Nuclear reactions between very light atoms similar to the reaction above are the energy source behind the sun and the hydrogen bomb. 

Fig. 14.11. Plot of deuterium retention in lithium samples exposed over a wide range of ion fluence (from [56]). The different symbols reflect the sample temperature during the plasma exposure. The solid line is a plot of the ion fluence. An estimate of the total energetic atom fluence arising from charge exchange, dissociation and ion bombardment is given by the dotted line...

The most common isotope of hydrogen has one proton and no neutrons in the nucleus, but 0.02% of hydrogen atoms have one proton and one neutron. This isotope of hydrogen is called deuterium, and is symbolized by the letter D. 

When it is desired to distinguish betw een isotopes, the approximate atomic mass is given as a superscript to the symbol thus is light hydrogen and is heavy hydrogen (deuterium). Oxygen consists mainly of with much smaller amounts of and When ec]ua-tions for nuclear reactions are written the atomic number is also often placed as a left subscript, thus ... 

A nuclear species (nuclide) is characterized by its atomic number Z (that is, the nuclear charge in units of e, or the number of protons in the nucleus) and its mass number A (the sum of the number of protons plus the number of neutrons in the nucleus). We denote an atom that contains such a nuclide with the symbol zX, where X is the chemical symbol for the element. The atomic number Z is sometimes omitted because it is implied by the chemical symbol for the element. Thus, JH (or H) is a hydrogen atom and (or C) is a carbon atom with a nucleus that contains six protons and six neutrons. Isotopes are nuclides of the same chemical species (that is, they have the same Z), but with different mass numbers A, and therefore different numbers of neutrons in the nucleus. The nuclear species of hydrogen, deuterium, and tritium, represented by JH, jH, and jH, respectively, are all members of the family of isotopes that belong to the element hydrogen. 

Hydrogen is the first element, and so has an atomic number of one. Its electronic configuration is Is1. There are three isotopes protium, deuterium and tritium, which may be represented by the symbols 1H, 2H or 3H, or alternatively, H, D or T. The cation of hydrogen is a bare proton, H+ (Is0) while the anion of hydrogen is called a hydride anion, H (Is ) (or more strictly, a protiide anion). 

The mass number for normal hydrogen atoms is 1 for deuterium, 2 and for tritium, 3. The composition of a nucleus is indicated by its nuclide symbol. This consists of the symbol for the element (E), with the atomic number (Z) written as a subscript at the lower left and the mass number (A) as a superscript at the upper left, By this system, the three isotopes of hydrogen are designated as H, H, and ]H. 

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