This research project reports the synthesis of nanocomposites of NiO (Nickel oxide)/H2O4Sn3(Hydroromarchite), using the coprecipitation method. Chemicals like Nickel Chloride, Tin chloride, Cesium fluoride were used for the formation of the powder sample of NiO/H2O4Sn3. The Obtained crystals of NiO/H2O4Sn3 were carefully analyzed using X-Ray diffraction (XRD). The Size was estimated through the Deby Scherer formula and was found to be∼38nm. The detailed structural characterization of nanocomposites of NiO/H2O4Sn3 was done through Rietveld refinements using fullprof software. An XRD finding suggests that NiO is cubic in shape with space group number 225. The Hermann-Mauguin symbol is Fm-3m. The Laue class value and point group are m-3m. The cell parameters obtained for NiO are: a= b= c= 4.176, while α = β= γ =90̊. The volume of the crystal is = 72.85 Å. Reciprocal cell parameters a*= b*=c*=0.2394, α*= β*= γ*= 90̊ and volume for reciprocal lattice is 0.01372. XRD studies for Hydroromarchite found that it has a tetragonal type of structure having a space group (114), the Hermann-Mauguin symbol is P-421C, the Laue class value and Point group value is 421 c. The obtained cell parameters are a= 7.920, b= 7.920, c= 9.104, and α = 90̊, β= 90̊, γ = 90̊. The volume of the crystal is = 571.03 Å. The data of reciprocal cell parameters were a*=0.1262, b*=0.1262, c*=0.1098 and α*=90̊, β*=90̊, γ*=90̊ and the value of reciprocal cell volume=0.00175 Å. Some applications of NiO and its composites in various fields are also summarized.