Averrhoa carambola: A Renewable Source of Oxalic Acid for the Facile and Green Synthesis of Divalent Metal (Fe, Co, Ni, Zn, and Cu) Oxalates and Oxide Nanoparticles

Table 2

Average crystallite sizes of the complexes and their decomposition products obtained using Debye-Scherrer equation.

Metal ion	Metal oxalate			Metal oxide
	Peak	Size (nm)	Average (nm)	Peak	Size (nm)	Average (nm)
Fe^2+	(202)	23.08	24.9	(012)	23.34	22.6
	(224)	27.10		(104)	24.35
	(022)	24.57		(024)	21.03
Co^2+	(002)	21.65	22.5	(220)	21.74	20.3
	(022)	24.06		(311)	21.98
	(224)	21.67		(400)	17.23
Ni^2+	(202)	17.42	19.7	(111)	14.80	14.5
	(004)	22.54		(200)	14.50
	(022)	19.17		(220)	14.05
Zn^2+	(002)	24.64	23.3	(100)	20.72	19.3
	(402)	22.12		(101)	19.76
	(022)	23.28		(102)	17.40
Cu^2+	(110)	16.25	15.0
	(011)	15.99		Not available
	(220)	12.78