This is a list of known oxidation states of the chemical elements, excluding nonintegral values. The most common states appear in bold. The table is based on that of Greenwood and Earnshaw, with additions noted. Oxidation state 0, which occurs for all elements, is implied by the column with the symbol of the element. The format of the table, which was devised by Mendeleev in 1889, shows the periodicity of the oxidation states of the elements.
== List ==
A figure with a similar format (shown below) was used by Irving Langmuir in 1919 in one of the early papers about the octet rule. The periodicity...
I remember my Physical Chemistry Professor saying that very tiny negative Kelvin temperatures have been achieved on the quantum level. Is this true?
Sodium tetrasulfide is an inorganic compound with the formula Na2S4. It is a yellow-orange solid that dissolved with hydrolysis in water. They are precursors to some specialty polymers and intermediates in prototypes of the sodium-sulfur battery.
== Synthesis and structure ==
It is produced through the reaction between elemental sulfur and sodium hydrosulfide in alcoholic solution:
2NaSH + 4 S → Na2S4 + H2S
The polysulfide anions adopt zig-zag chains of sulfur atoms. The S-S distances are about 2.05 Å and the S-S-S-S dihedral angles are around 90°.
== Reactions and applications ==
Upon treatment...
For an ideal gas, we have
$$C_p - C_V = nR$$
where
$C_p$ is heat capacity at constant pressure,
$C_V$ is heat capacity at constant volume,
$n$ is amount of substance, and
$R=8.3144598(48)\ \mathrm{J\ mol^{-1}\ K^{-1}}$[source] is the molar gas constant.
How can I prove this?
The left hand isomer is clearly the kinetically favoured product and the right hand isomer is the thermodynamically favoured product. However, I have no idea why. Can you explain?
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The Periodic Table
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