Multiple choice Irregularity in the arrangement of constituent particles in solids is called ________. Stoichiometric defect Crystal defect Vacancy defect Frenkel defect Impurities defect Reveal answer Fill a bubble to check yourself B Correct answer Explanation Yes, the irregularity in the arrangement of constituent particles in solids is called crystal defect or imperfection in solids. There are two types of crystal defects; point defects and line defects.