Protium properties

Table 3.1 Atomic properties of hydrogen (protium), deuterium, and tritium...

Properties of Deuterium Properties of deuterium are similar to those of protium. For example, it is colourless, odourless and tasteless. It is insoluble in water and bad conductor of heat. Its atomicity is 2. Some other physical constants these isotopes are ... 

Of all the elements, isotope effects see Isotope Effect) are greatest for hydrogen, justifying the use of distinctive names for the hydrogen isotopes protium, deuterium, and tritium. However, the chemical properties of H, D, and T are essentially identical, except in matters such as equilibrium constants. The isotopes of hydrogen are extensively used as tracers in deuterium- or tritium-labeled compounds. 

The 10% mass change in water by the replacement of protium by deuterium results in substantial changes in many commonly known properties of water. In Table 3, a number of physical properties of normal water, FI2O, and heavy water, D2O, are compared. The viscosity of D2O is 25% higher than that of H2O at 25 °C, which is the most conspicuous difference between H2O and D2O. 

Two or more atoms of the same element that contain different numbers of neutrons are said to be isotopes. An atom of a specific isotope is called a nuclide. Isotopes have similar chemical properties. Hydrogen has three important isotopes H (pro-tium), 2H (deuterium), and 3H tritium). 99.98% of naturally occurring hydrogen is protium. Examples of three isotopes for carbon are ... 

One further interesting development took place in 1932, when Urey discovered isotopes of hydrogen. In these cases, the masses of the isotopes differ from each other by as much as 100% (Urey Grieff, 1935). The properties of these isotopes are definitely not the same. For example water (mostly protium oxide) has a boiling point of 100°C, whereas the value for deuterium oxide is 104°C. Strictly speaking, Fajans had been correct to doubt replaceability, but the problem is only significant in isotopes with very low masses, and Urey s discovery did not change the chemical definition of an element in any way. 

Tabulated data of good accuracy (say better than 0.1%) for some or all of Vm. P and Z are available in a wide range of pressures and temperatures for protium and, to a lesser extent, deuterium. A comprehensive tabulated source is Vargaftik (1975). Other sources are discussed by Hemmes et al. (1986). The most recent, most comprehensive and generally most accurate source is contained in the commercially available National Institute of Standards and Technology (USA) Reference Fluid Thermodynamic and Transport Properties database (REFPROP, URLhttp //www.nist.gov/srd/nist23.htm), in which are embedded advanced equations of state for protium (Jacobsen et al., 2007) and deuterium (McCarty, 1989). 

Table 1. Some atomic properties of protium, deuterium and tritium.

Properties of any solution depend on the content of one more minuscule in size but very important particle, H This ion represents protium nucleus without the electron shell, i.e., elementary particle proton with mass 1.67-10" kg and electric charge +1. Due to a small size (radius 10 cm whereas radius of the other ions is on the order of 10 cm) proton generates string electric field and in water solutions always exists in hydrated form... 

It is generally assumed that the chemical properties of difierent isotopes of one element are identical. However, the considerable difference between the masses of protium and deuterium leads to measurable differences in the chemical properties of the elements themselves and of their compounds that are much more pronounced than for the isotopes of other elements (600-602). The slight but significant toxicity of D2O is also a result of this phenomenon (603). 

Because an atom of deuterium is about twice as massive as an atom of protium, the properties of deuterium-containing substances varj somewhat from those of the protium-containing analog. For example, the normal melting and boiling points of D2O are 3.81 °C and 101.42 °C, respectively, versus 0.00 °C and 1(X).(X) °C for H2O. Not surprisingly, the... 

A new family of azaphilones has been isolated from Aspergillus deflectus and identified as (6a - e) by the usual combination of spectral data and chemical properties. Full details have now appeared of biosynthetic studies on citrinin (7), a metabolite of Penicillium citrinum. using protium as tracer in... 

The vibrational wavenumber, a = 2897 cm calculated above is for a H— C1 molecule. But protium, H, is not the only hydrogen isotope found in nature there is deuterium, (D), with a mass equal to two atomic units, and tritium, (T), with atomic mass of 3 amu. The hydrogen atoms found in nature are a mixture of all three isotopes and, like in any mixture, its properties - and mass - are the average value, m(H) = 1.0078 amu. Likewise, chlorine in nature is a mixture of about 75% of isotope C1 and about 25% of isotope C1, so the average mass of Cl atoms is 35.453 amu or that of CI2 molecules twice this. How does this affect molecular vibrations and vibrational spectra ... 

Hydrogen occurs in nature as a mixture of three isotopes protium H, deuterium H or D and tritium H or T. The last is radioactive. Some properties of nuclides of the three isotopes are collected in Table 9.1. 

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