International Journal of Academic and Applied Research (IJAAR)   Year: 2021 | Volume: 5 | Issue: 4 | Page No.: 145-150 The Change of Absorption Coefficient and Energy Gap of Hashab Gum Arabic when Doped with Iodine Mubrarak Dirar Abd-Alla, Nuha Hassan Kinash , Ahmed Al hassan Alfaki , Abdalskhi .S.M.Hamed. Abstract: Five samples from Hashab Gum Arabic were doped with iodine having concentrations (0.1, 0.2, 0.3, 0.4, 0.5 ppm).The energy gap were studied using ultraviolet spectrophotometer. The d-spacing and the crystal nano sizes were studied using X-ray diffraction device. Increasing iodine concentration decreases nano crystal size and d-spacing. The increase of iodine concentration increases the energy gap to take the values (2.453, 2.467, 2.473, 2.482, and 2.493 eV).