The IUPAC name of Calconcarboxylic acid is 3-hydroxy-4-[(2Z)-2-(2-oxo-4-sulfonaphthalen-1-ylidene)hydrazinyl]naphthalene-2-carboxylic acid. With the CAS registry number 3737-95-9, it is also named as Patton and Reeder's indicator. It is dark violet powder which is slightly soluble in water and ethanol, soluble in alkali and ammonia. The neutral water solution is purple. When the pH is not greater than 10, the water solution is red, and it is light blue at the pH 12 to 14. And it is stable and incompatible with strong oxidizing agents. In addition, Calconcarboxylic acid is used as complexometric indicator in the determination of Calcium.

The other characteristics of this product can be summarized as: (1)ACD/LogP: 2.86; (2)# of Rule of 5 Violations: 0; (3)ACD/BCF (pH 5.5): 1; (4)ACD/BCF (pH 7.4): 1; (5)ACD/KOC (pH 5.5): 1; (6)ACD/KOC (pH 7.4): 1; (7)#H bond acceptors: 9; (8)#H bond donors: 4; (9)#Freely Rotating Bonds: 6; (10)Index of Refraction: 1.734; (11)Molar Refractivity: 109.25 cm³; (12)Molar Volume: 272.4 cm³; (13)Polarizability: 43.31×10^-24 cm³; (14)Surface Tension: 72.4 dyne/cm; (15)Rotatable Bond Count: 4; (16)Tautomer Count: 35; (17)Exact Mass: 438.052172; (18)MonoIsotopic Mass: 438.052172; (19)Topological Polar Surface Area: 162; (20)Heavy Atom Count: 31; (21)Complexity: 907.

When you are using this chemical, please be cautious about it as the following:
It is irritating to eyes, respiratory system and skin. In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. If you want to contact this product, you must wear suitable protective clothing, gloves and eye/face protection.

People can use the following data to convert to the molecule structure. 
1. SMILES: OC(=O)c4cc1ccccc1c(N=Nc2c3ccccc3c(cc2O)S(O)(=O)=O)c4O;
2. InChI: InChI=1/C21H14N2O7S/c24-16-10-17(31(28,29)30)13-7-3-4-8-14(13)18(16)22-23-19-12-6-2-1-5-11(12)9-15(20(19)25)21(26)27/h1-10,24-25H,(H,26,27)(H,28,29,30).