Table 9.

Comparison of literature values for the vibrational modes in α-Ni(OH)₂.

	mode frequency (cm−1)
peak assignment	[38]	literature frequency
Raman
lattice mode	460	461 [194], 451–460 [227], 462–464 [232], 460 [233]
lattice mode	495	—
second-order lattice mode	∼790	—
second-order lattice mode	∼1075	—
O−H bend, lattice OH	∼1400	—
O−H bend, layer H2O	1590–1620	—
O−H bend, free H2O	1630	—
O−H stretch, free H2O	∼3240, ∼3380, 3515	—
O−H stretch, lattice OH/layer H2O	3590, 3620, 3642–3650	3625 [159], 3637 [194], 3657 [227], 3650–3653 [232], 3656 [233]
infrared
lattice mode	—	400 [40], 380 [161]
lattice mode	—	460 [40], 461 [139], 480 [161], 474 [173], 480 [238]
lattice mode	≤650−670	625 [40], 662 [139], 650 [161], 645 [173], 650–655 [238]
combination lattice mode	835	—
combination lattice mode	1055	1055 [139]
O−H bend, lattice OH	1380–1390	1400 [139]
O−H bend, lattice OH	1480–1490	1540 [139]
O−H bend, layer H2O	1600	1650 [40], 1640 [139], 1600 [161], 1650 [237], 1615–1620 [238]
O−H bend, free H2O	1630	—
O−H stretch, free H2O	3220/3240, 3380/3390, 3500/3515	3350 [40], ∼3500 [161], ∼3400 [173], 3350 [237], ∼3500 [238]
O−H stretch, lattice OH/layer H2O	3570, 3600–3640	∼3600 [161], ∼3600 [173]