Lecture8_AlkaliMetals_bandw

The blue solutions decompose over time and loose

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

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; Nuclear properties; Chemical and physical properties; Reactivity: – – – – • • • • CHMB31H3 With water; With H2 (stability of hydrides); With X2 (with halogens; stability of halides); With O2 (different oxides; reactivi...
View Full Document

Ask a homework question - tutors are online