The Mercaptodiacetic acid is an organic compound with the formula C₄H₆O₄S. The IUPAC name of this chemical is 2-(carboxymethylsulfanyl)acetic acid. With the CAS registry number 123-93-3, it is also named as 2,2'-Sulfanediyldiacetic acid. Besides, it is a greyish crystalline powder, which is used as detection of copper, lead, mercury, silver.

Physical properties about Mercaptodiacetic acid are: (1)ACD/LogP: -0.78; (2)ACD/LogD (pH 5.5): -4.37; (3)ACD/LogD (pH 7.4): -5.53; (4)ACD/BCF (pH 5.5): 1; (5)ACD/BCF (pH 7.4): 1; (6)ACD/KOC (pH 5.5): 1; (7)ACD/KOC (pH 7.4): 1; (8)#H bond acceptors: 4; (9)#H bond donors: 2; (10)#Freely Rotating Bonds: 4; (11)Polar Surface Area: 77.9 Å²; (12)Index of Refraction: 1.561; (13)Molar Refractivity: 31.7 cm³; (14)Molar Volume: 97.7 cm³; (15)Polarizability: 12.56×10^-24cm³; (16)Surface Tension: 72.7 dyne/cm; (17)Density: 1.535 g/cm³; (18)Flash Point: 181.8 °C; (19)Enthalpy of Vaporization: 68.6 kJ/mol; (20)Boiling Point: 377 °C at 760 mmHg; (21)Vapour Pressure: 1.01E-06 mmHg at 25°C.

Uses of Mercaptodiacetic acid: it can be used to produce [1,4]oxathiane-2,6-dione by heating. It will need reagent Ac₂O with reaction time of 3 hours. The yield is about 87%.

When you are using this chemical, please be cautious about it as the following:
It can cause burns. In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. Besides, this chemical is irritating to eyes, respiratory system and skin. When you are using it, wear suitable gloves and eye/face protection. In case of accident or if you feel unwell seek medical advice immediately (show the label where possible).

You can still convert the following datas into molecular structure:
(1)SMILES: O=C(O)CSCC(=O)O
(2)InChI: InChI=1/C4H6O4S/c5-3(6)1-9-2-4(7)8/h1-2H2,(H,5,6)(H,7,8)
(3)InChIKey: UVZICZIVKIMRNE-UHFFFAOYAB
(4)Std. InChI: InChI=1S/C4H6O4S/c5-3(6)1-9-2-4(7)8/h1-2H2,(H,5,6)(H,7,8)
(5)Std. InChIKey: UVZICZIVKIMRNE-UHFFFAOYSA-N

The toxicity data is as follows: