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Unformatted text preview: ) NH4+ + NH2- K = [NH4+][NH2-] = 5.1.10-27 mol2/dm6 • Liquid NH3 dissolves alkali metals producing deep blue solutions:
M (s) Liquid NH3 M+ (sol) + e- (sol) Metastable blue solutions • These solutions are excellent reducing agents.
• The blue solutions decompose over time and loose colour (the
free electrons reduce ammonia on standing):
2NH3 (l) +2e- (sol)
CHMB31H3 2 NH2- (sol) + H2
The Chemistry of Group 1 Under kinetic control give
metal amides, MNH2, very
useful strong bases.
22 Alkalides and Electrides
• Alkalides are alkali metal anions (M-) with an ns2 electronic
configuration (known for all but Li)
• If 0.5 equivalents of crypt-222 is added to a Na solution in
CH3CH2NH2 a golden yellow complex [Na(crypt-222)]Na containing
Na- anion, can be isolated.
• If 1 equivalent of crypt is used, or 2 equivalents of a crown ether
electrides can be isolated – these contain a free electron in their
structure, i.e. [M(crypt-222)]+e-. [Na(crypt-222)]Na structure
CHMB31H3 [Cs(18-crown-6)2]e structure The Chemistry of Group 1 23 Overview
• Occurrence and isolation;
Chemical and physical properties;
• CHMB31H3 With water;
With H2 (stability of hydrides);
With X2 (with halogens; stability of halides);
With O2 (different oxides; reactivi...
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