Table: polyphenyl_ether_properties
Columns: polyphenyl_ether
appearance
thermal_stability_f_c
viscosity_cst_at_100_f_38_c
viscosity_cst_at_210_f_99_c

Question: What does Polyphenyl Ether of 3- and 4-ring oxythio look like?
SQL: SELECT "appearance" FROM polyphenyl_ether_properties WHERE "polyphenyl_ether" = '3- and 4-ring oxythio'