Hydrides saltlike

The nature of a binary hydride is related to the characteristics of the element bonded to hydrogen (Fig. 14.8). Strongly electropositive metallic elements form ionic compounds with hydrogen in which the latter is present as a hydride ion, H. These ionic compounds are called saline hydrides (or saltlike hydrides). They are formed by all members of the s block, with the exception of beryllium, and are made by heating the metal in hydrogen ... 

CH2=CH2 + H20 - CH3CH2OH. hydride A binary compound of a metal or metalloid with. hydrogen the term is often extended to include all binary compounds of hydrogen. A saline or saltlike hydride is a compound of hydrogen and a strongly electropositive metal a molecular hydride is a compound of hydrogen and a nonmetal a metallic hydride is a compound of certain d-block metals and hydrogen. 

Generally chemists recognize three broad types of binary hydrides (that is, compounds containing hydrogen and one additional element). These are molecular hydrides, saltlike hydrides, and interstitial hydrides. 

Thus, owing to the endothermic character of the H" ion, only the most electropositive metals—the alkalis and the alkaline earths—form saline or saltlike hydrides, such as NaH and CaH2. The ionic nature of the compounds is shown by their high conductivities just below or at the melting point and by the fact that on electrolysis of solutions in molten alkali halides hydrogen is liberated at the anode. 

M-bH2 —MH2 Ionic saltlike hydrides formed at high temperatures by Ca, Sr, and Ba... 

Ionic (Saltlike) Hydrides With very reactive metals, such as those in Group 1A(1) and the larger members of Group 2A(2) (Ca, Sr, and Ba), hydrogen forms saltlike... 

The alkali metals reduce hydrogen to form ionic (saltlike) hydrides ... 

Thus, in air, the metals tarnish rapidly, so Na and K are usually kept under mineral oil (an unreactive liquid) in the laboratory, and Rb and Cs are handled with gloves under an inert argon atmosphere. And, finally, the Group 1A(1) elements reduce molecular hydrogen to form ionic (saltlike) hydrides ... 

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