Synthesis of lead(II) oxalate hydrate (PbC₂O₄.xH₂O) crystal in silica gel

Lead(II) oxalate (PbC₂O4.xH₂O) crystal has polymeric structure via chelated bridging ligand of oxalate. Gel technique is promising for growing PbC₂O_4.xH₂O single crystal with the advantage of forming only few crystal nuclei but could grow with larger size. The purpose of this research are to synthesis PbC₂O4.xH₂O crystal in silica gel and to study the properties of synthesized crystal at optimum conditions. The crystals were synthesized in silica gel using U-tube glass. Pb(NO₃₎₂ and Na2C₂O₄ as supernatant solution was added in each side (in 1:1 ratio) with growth time of three weeks. The pH of gel was varied between 4.5-5.1 as well as the supernatant concentration, which is 0.05-0.20 M. The synthesized crystals from optimum condition were characterized using SEM, FTIR, powder XRD. The optimum conditions was obtained at pH of 4.8 and concentration of Pb(NO₃₎₂ and Na₂C₂O₄ of 0.10 M with 23.34% yield. The synthesized crystals were white needle-shaped with length of 678 micron and soluble in concentrated HNO₃. The characterization using IR and powder XRD indicate that the synthesized crystal was lead(II) oxalate hydrate (PbC₂O₄.xH₂O) with crystal system of triclinic.