Single crystals of holmium oxalate heptahydrate are grown by gel diffusion method using organic agar gel as a medium of growth. The crystals grow in the agar gel with hexagonal morphology having well defined habit faces Powder X-ray diffraction results show that the crystals belong to monoclinic system bearing the space group P2
1/c with cell parameters; a = 12.197
?
, b = 11.714 , c = 6.479 , α = 90°, β = 120.12°, γ = 90°, V = 799.6?
3. Fourier transform Infrared spectrum of the crystals shows the presence of water and other associated functional groups. Thermogravimetric analysis support the presence of 7 H
2O molecules associated with holmium oxalate crystal lattice. The thermal decomposition in the nitrogen atmosphere leads to the formation of holmium oxide as the final product.