indole butyric acidindole-3-butyric acid (1h-indole-3-butanoic acid, iba) is a white to light-yellow crystalline solid, with the molecular formula c12h13no2. It melts at 125 °c in atmospheric pressure and decomposes before boiling. Iba is a plant hormone in the auxin family and is an ingredient in many commercial horticultural plant rooting products.other names : indole-3-butyric acid, 3-indolebutyric acid, indolebutyric acid ibacas number: 133-32-4chemical formula : c12h13no2molar mass : 203.24 g·molappearance : white to light yellow crystals