87.1 Electrolyte and electrolytic solution Hydration of ion The water molecules in the hydration sphere and bulk water have different properties which can be distinguished by spectroscopic techniques such as nuclear magnetic resonance(NMR), infrared spectroscopy (R), and Xrd etc Coordination number. Lit:4,K+:6 Coordination number? Primary solvation shell 4-9. 6 is the most common number Secondary solvation shell 6-8. for A+ and Cr3+: 10-20Hydration of ion Coordination number: Li+ : 4, K+ : 6 Primary solvation shell: 4-9, 6 is the most common number Secondary solvation shell: 6-8, for Al3+ and Cr3+: 10-20 The water molecules in the hydration sphere and bulk water have different properties which can be distinguished by spectroscopic techniques such as nuclear magnetic resonance (NMR), infrared spectroscopy (IR), and XRD etc. Coordination number? §7.1 Electrolyte and electrolytic solution