This page provides supplementary chemical data on formic acid.
Material Safety Data Sheet
The handling of this chemical may incur notable safety precautions. It is highly recommend that you seek the Material Safety Datasheet (MSDS) for this chemical from a reliable source and follow its directions. MSDS from FLUKA in the SDSdata.org database Science Stuff
Structure and properties
Structure and properties Index of refraction, nD 1.3714 at 20 °C Abbe number? Dielectric constant, εr 58.5 ε0 at 16 °Cmeasured at 400 MHz Bond strength ? Bond lengthMorrison, Robert Thornton and Boyd, Robert Neilson, Organic Chemistry, 2nd ed. Allyn and Bacon 1972, p. 596 C=O bond: 123 pmC–OH bond: 136 pm Bond angle ? Magnetic susceptibility ? Surface tension 37.67 dyn/cm at 20 °C ViscosityLange's Handbook of Chemistry, 10th ed. pp. 1669–1674 2.2469 mPa·s at 10 °C 1.7844 mPa·s at 20 °C 1.2190 mPa·s at 40 °C 0.5492 mPa·s at 100 °C
Thermodynamic properties
Phase behavior Triple point 281.40 K (8.25 °C), 2.2 kPa Critical point 588 K (315 °C), 5.81 MPa Std enthalpy changeof fusion, ΔfusHo +12.68 kJ/mol Std entropy changeof fusion, ΔfusSo +45.05 J/(mol·K) at 8.25 °C Std enthalpy changeof vaporization, ΔvapHo +23.1 kJ/mol Std entropy changeof vaporization, ΔvapSo +61.8 J/(mol·K) Solid properties Std enthalpy changeof formation, ΔfHosolid ? kJ/mol Standard molar entropy,Sosolid ? J/(mol K) Heat capacity, cp 74.5 J/(mol K) at –22 °C82.8 J/(mol K) at 0 °C Liquid properties Std enthalpy changeof formation, ΔfHoliquid –425.5 kJ/mol Standard molar entropy,Soliquid 129.0 J/(mol K) Enthalpy of combustion, ΔcHo –254.6 kJ/mol Heat capacity, cp 101.3 J/(mol K) at 20–100 °C Gas properties Std enthalpy changeof formation, ΔfHogas –362.6 kJ/mol Standard molar entropy,Sogas 251.0 J/(mol K) Heat capacity, cp 45.68 J/(mol K) at 25 °C
Vapor pressure of liquid P in mm Hg 1 10 40 100 400 760 T in °C –20.0(s) 2.1(s) 24.0 43.8 80.3 100.6
Table data obtained from CRC Handbook of Chemistry and Physics, 44th ed. The "(s)" notation indicates temperature of solid/vapor equilibrium. Otherwise the data is temperature of liquid/vapor equilibrium.
Distillation data Vapor-liquid Equilibrium for Formic acid/WaterP = 760 mmHg BPTemp.°C % by mole water liquid vapor 102.3 4.05 2.45 104.6 15.5 10.2 105.9 21.8 16.2 107.1 32.1 27.9 107.6 40.9 40.2 107.6 41.1 40.5 107.6 46.4 48.2 107.1 52.2 56.7 106.0 63.2 71.8 104.2 74.0 83.6 102.9 82.9 91.7 101.8 90.0 95.1
Spectral data
UV-Vis λmax ? nm Extinction coefficient, ε ? IR Major absorption bands ? cm−1 NMR Proton NMR Carbon-13 NMR Other NMR data MS Masses of main fragments
Safety data
Formic acid EINECS number 200-579-1 Safety data EU classification Corrosive (C) PEL 5 ppm (9 mg/m3) IDLH 30 ppm Autoignition temperature 520 °C Explosive limits 18–51%
References