2,5-Thiophenedicarboxylic acid

Empirical Formula: C₆H₄O₄S
Molecular Weight: 172.1586 
Index of Refraction: 1.662
Molar Refractivity: 38.49 cm³
Molar Volume: 103.9 cm³
Surface Tension: 83.9 dyne/cm
Density: 1.655 g/cm³
Flash Point: 222.7 °C
Enthalpy of Vaporization: 74.03 kJ/mol
Boiling Point: 444.6 °C at 760 mmHg
Vapour Pressure: 1.1E-08 mmHg at 25 °C
Melting point: >300 °C(lit.)
Appearance: White to light yellow crystal powder
Structure of 2,5-Thiophenedicarboxylic acid (CAS NO.4282-31-9):
                        
Product Category of 2,5-Thiophenedicarboxylic acid (CAS NO.4282-31-9): Thiophenes;Thiophens;Functional Materials;Reagents for Conducting Polymer Research;Thiophene Derivatives (for Conduting Polymer Research);Thiophen;Heterocyclic Building Blocks

Hazard Codes: Xi
Risk Statements: 36/37/38
R36/37/38:Irritating to eyes, respiratory system and skin.
Safety Statements: 26-36-37/39 
S26: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. 
S36:Wear suitable protective clothing. 
S37/39:Wear suitable gloves and eye/face protection.

 2,5-Thiophenedicarboxylic acid , its cas register number is 4282-31-9. It also can be called Thiophene-2,5-dicarboxylic acid ; and NSC 81789 . It is hazardous, so the first aid measures and others should be known. Such as: When on the skin: first, should flush skin with plenty of water immediately for at least 15 minutes while removing contaminated clothing. Secondly, get medical aid. Or in the eyes: Flush eyes with plenty of water for at least 15 minutes, occasionally lifting the upper and lower eyelids. Then get medical aid soon. While, it's inhaled: Remove from exposure and move to fresh air immediately. Give artificial respiration while not breathing. When breathing is difficult, give oxygen. And as soon as to get medical aid. Then you have the ingesting of the product: Wash mouth out with water, and get medical aid immediately. Notes to physician: Treat supportively and symptomatically.
In addition, 2,5-Thiophenedicarboxylic acid (CAS NO.4282-31-9) is not compatible with strong oxidizing agents, and you must not take it with incompatible materials. And also prevent it to broken down into hazardous decomposition products: Carbon monoxide, carbon dioxide, sulfur oxides (SO_x), including sulfur oxide and sulfur dioxide.