Zinc chloride hydroxide monohydrate is a zinc hydroxy compound with chemical formula Zn₅(OH)₈Cl₂·H₂O. It is often referred to as tetrabasic zinc chloride (TBZC), basic zinc chloride, zinc hydroxychloride, or zinc oxychloride. It is a colorless crystalline solid insoluble in water. Simonkolleite has been shown to be a desirable nutritional supplement for animals.