Affinity nitrogen, oxygen

It is easy to reduce anhydrous rare-earth hatides to the metal by reaction of mote electropositive metals such as calcium, lithium, sodium, potassium, and aluminum. Electrolytic reduction is an alternative in the production of the light lanthanide metals, including didymium, a Nd—Pt mixture. The rare-earth metals have a great affinity for oxygen, sulfur, nitrogen, carbon, silicon, boron, phosphoms, and hydrogen at elevated temperature and remove these elements from most other metals. 

Which element of each of the following pairs has the higher electron affinity (a) oxygen or fluorine (b) nitrogen or carbon (c) chlorine or bromine (d) lithium or sodium ... 

The importance of solvent effects has been outlined in Section 2.2.1. An illustration with some of the fluoroionophores described in this section is given in Table 2.2. For alkali and alkaline-earth metal ions, the stability constants are higher in acetonitrile than in methanol these cations are indeed hard and have a stronger affinity for oxygen atoms (hard) than for nitrogen atoms (soft). In contrast, the soft silver atom has a strong affinity for nitrogen atoms and no complexation is observed in acetonitrile, whereas complexes in methanol, ether, and 1,2-dichloromethane are formed. 

After a plate has been exposed to the mobile-phase solvent for the required time, the compounds present can be viewed by several methods. Polynuclear aromatic hydrocarbons, other compounds with conjugated systems, and compounds containing heteroatoms (nitrogen, oxygen, or sulfur) can be viewed with long-and short-wave ultraviolet light. The unaided eye can see other material, or the plates can be developed in iodine. Iodine has an affinity for most petroleum compounds, including the saturated hydrocarbons, and stains the compounds a reddish-brown color. 

This view Michael confirmed in 1935 when he emphasized [2] that in a molecule of nitric acid the dominating factor, which facilitated the reaction, was the affinity of oxygen for hydrogen and of nitrogen for the aryl group. 

This solution has a remarkable affinity for oxygen. It is used to remove traces of oxygen from gases such as nitrogen or argon when it is desirable to render them absolutely oxygen-free. This solution has a capacity of about 800 mL of oxygen. The color fades and the solution turns brown when it is exhausted. 

This method is particularly successful for those metals that have a greater affinity for oxygen compared to nitrogen and is generally rendered more facile due to the higher volatility of liberated dialkylamines. 

---