SF6_props returns thermodynamic properties of sulfur hexafluoride as a function of pressure (MPa) and temperature (K).
SF6_properties = SF6_props(0.101,295);
SF6_sound_speed = SF6_properties.c;
0.1 MPa <= P_MPa <= 150 MPa
210 K <= T_K <= 625 K
Note: There are some "edge effects" in the interpolation. If you enter pressure or temperature values that are near the outer bounds of their valid range, you may get a NaN result. Sorry about that.
CREDIT WHERE CREDIT IS DUE:
Values are linearly interpolated from data found in Table 29 of:
A Reference Equation of State for the Thermodynamic Properties of Sulfur Hexafluoride (SF_6) for Temperatures from the Melting Line to 625 K and Pressures up to 150 MPa.
C. Guder and W. Wagner, J. Phys. Chem. Ref. Data 38, 33 (2009),
I cannot attest to the accuracy of the source data and I cannot guarantee that this function will flawlessly retrieve the appropriate data from the table. Who knows, I could've made some errors in transferring the tabulated data. Further, this function relies upon linear interpolation of sometimes sparse data to describe the properties of a rather unique substance, so, inherently there are many approximations and there's plenty of room for error. Still, hopefully these numbers will be in the right ballpark.
If you use this function along the way to publishing, you do not need to cite me in any way. However, you should most certainly give credit to Guder and Wagner. Read their paper. It's good.