Question

What is the melting point of meso-stilbene dibromide?

Answer 1

The meso isomer, which has a mirror plane down its vertical symmetry axis, would be the `("R","S")` stereoisomer, because mirroring the `"R"` configuration gives you the `"S"` configuration.

So, it looks like either of the above structures.

Based on the following references, I see that the melting point RANGE is close to `241^@ "C"`.

I used Scifinder and found two probable melting point ranges:

• `239^@ ~ 241^@ "C"`
  Schroth, Werner; Zeitschrift fuer Chemie 1977, V17(2), P56 CAPLUS

• `236^@ ~ 237^@ "C"`
  Fieser, Louis F.; Journal of Chemical Education 1954, V31, P291-7 CAPLUS
  Yusubov, M. S.; Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya 1991, (4), P868-73 CAPLUS)

And additional references also say about `241^@ "C"`.

http://www.cengage.com/chemistry/book_content/049501334X_gilbert/prelabs/f_z_msds_gilbert_withtoc.htm#_Toc122330419

https://www.nwmissouri.edu/naturalsciences/sds/0-9/1%202-Dibromo-1%202-diphenylethane.pdf (pg. 3)