High-Pressure Synthesis and Study of NO⁺NO₃⁻ and NO₂⁺NO₃⁻ Ionic Solids

Table 2

Total irreducible representation and spectral activity of the monoclinic and aragonite-type NO⁺NO₃⁻ crystal for (a) 𝐶²_2ℎ (𝑃2₁/𝑚), (b) 𝐶⁹_2𝜈 (𝑃𝑛𝑎2₁), and (c) 𝐷¹⁶_2ℎ (𝑃𝑛𝑚𝑎) space group.

(a)

Crystal symmetry 𝐶2ℎ	Translations	Acoustical	Rotation	Intramolecular	Spectral
	(lattice vibrations)	vibrations	(libration)	vibrations	activity 𝐶2ℎ
Ag	4		2	5	R
Au	1	1	3	2	IR
Bg	2		3	2	R
Bu	2	2	2	5	IR
Total vibrations	9	3	10	14

(b)

Crystal symmetry 𝐶2𝜈	Translations	Acoustical	Rotation	Intramolecular	Spectral
	(lattice vibrations)	vibrations	(libration)	vibrations	activity 𝐶2𝜈
A1	5	1	5	7	R, IR
A2	6		5	7	R
B1	5	1	5	7	R, IR
B2	5	1	5	7	R, IR
Total vibrations	21	3	20	28

(c)

Crystal symmetry 𝐷2ℎ	Translations	Acoustical	Rotation	Intramolecular	Spectral
	(lattice vibrations)	vibrations	(libration)	vibrations	activity 𝐷2ℎ
Ag	4		1	5	R
B1u	3	1	1	5	IR
B2u	3	1	1	5	IR
B3g	4		1	5	R
Au	2		4	2
B1g	2		4	2	R
B2g	2		4	2	R
B3u	1	1	4	2	IR
Total vibrations	21	3	20	28