Raman Study on Pompeii Potteries: The Role of Calcium Hydroxide on the Surface Treatment

Table 2

(a) Fundamental vibrational modes of the carbonates according to [3, 4]. (b) Raman bands in some carbonates and hydroxyl-carbonates.

(a)

Mode	Symmetry	Selection rules	Frequencies (cm^−1)
Nondegenerate symmetric stretch	A^′1	Raman	1064
Nondegenerate asymmetric (out of plane) bend	A^′′2	IR	Near 800
Doubly degenerate asymmetric stretch	E^′	IR + Raman	1415
Doubly degenerate symmetric (in-plane) bend	E^′	IR + Raman	680

(b)

Calcite; [5, 6]	Siderite; [7, 8]	Aragonite; [9–11]	Strontianite; [10, 12]	Vaterite; [13]	Azurite; [7, 14]	Free; [15, 16]	Assignment; [15, 16]
89					112		R (CO3)
162	190			212	165; 194		T (Ca, CO3)
288	294	284	246	287	281		T (Ca, CO3)
	506				540		T (Ca, Fe, CO3)
716	731; 742	701; 705	701; 711	750	739; 764	680	4-Symmetric CO3 bending mode
		853	855		815; 835	879	2-Asymmetric CO3 bending mode
					937; 952		O–H out-of-plane bending mode
1092	1087	1085	1074	1090	1095	1063	1-Symmetric CO3 stretching mode
1437		1465; 1547	1408; 1447	1441	1421; 1431; 1462	1415	3-Asymmetric CO3 stretching mode
					1582		O–H bending mode
1754	1726; 1733						1 + 4