Table 1.

A brief summary on the structure elucidation of xanthones using spectroscopy techniques.

Xanthone Structure	IR (cm−1)	UV (nm)	1H-NMR (ppm)	13C-NMR (ppm)
Csp2-H	3000–3100	-	6–9	-
C=O	1650–1720	200–400	-	176
C=C aromatic	1450–1600		-	126 (C-1)
				124 (C-2)
				135 (C-3)
				118 (C-4)
				156 (C-4a)
				121 (C-8a)
C-O-C ether	1000–1200	-	-	-
O-H	3300–3500	-	9–10 (C-2 or C-7)	-
			9–11 (C-4 or C-5)
			10–11 (C-3 or C-6)
			12–14 (C-1 or C-8)