Molecular Structure of 3-Methyl-4-pyridinecarboxylic acid (CAS NO.4021-12-9):

IUPAC Name: 3-methylpyridine-4-carboxylic acid 
Empirical Formula: C₇H₇NO₂
Molecular Weight: 137.136
H bond acceptors: 3
H bond donors: 1
Freely Rotating Bonds: 1
Polar Surface Area: 50.19 Å²
Index of Refraction: 1.561
Molar Refractivity: 36.099 cm³
Molar Volume: 111.462 cm³
Surface Tension: 53.319 dyne/cm
Density: 1.23 g/cm³
Flash Point: 188.8 °C
Enthalpy of Vaporization: 67.27 kJ/mol
Boiling Point: 388.569 °C at 760 mmHg
Vapour Pressure: 0 mmHg at 25°C
Product Categories: pharmacetical; Pyridines
SMILES: Cc1cnccc1C(=O)O
InChI: InChI=1/C7H7NO2/c1-5-4-8-3-2-6(5)7(9)10/h2-4H,1H3,(H,9,10)

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. 
S36/37/39:Wear suitable protective clothing, gloves and eye/face protection.
HazardClass: Irritant

  3-Methyl-4-pyridinecarboxylic acid , with CAS number of 4021-12-9, can be called 4-pyridinecarboxylic acid, 3-methyl- ; 3-Methyl-isonicotinic acid ; 3-methylpyridine-4-carboxylic acid .