Low-temperature　eutectic　region　(LTER)　of　a　molten-salt　mixture　is　defined　as　the　temperature　range　between　the　melting　temperature　of　the　mixture　and　the　highest　melting　temperature　of　its　components.　The　melting　temperature　of　a　salt　mixture　is　usually　lower　than　that　of　its　components　if　the　mixture　presents　an　eutectic　behavior,　that　is,　the　temperature　in　the　LTER　of　a　mixture　of　molten-salts　may　be　below　the　melting　temperature　of　its　components.　A　single　salt　may　be　not　in　liquid　state　in　this　temperature　range.　The　properties　of　single　mixture　components　in　the　LTER　are　often　necessary　but　cannot　be　directly　measured　through　experiments　in　calculating　the　thermophysical　properties　of　salt　mixtures　such　as　density,　viscosity,　thermal　conductivity,　etc.　In　this　paper,　dependence　of　density　and　thermal　conductivity　on　temperature　is　theoretically　derived,　and　applied　to　experimental　data.　It　is　proved　that　experimental　density　of　single　molten　salts　can　be　well　fitted　using　theoretical　models.　Experimentally,　thermal　conductivity　data　can　be　obtained　by　steady　state　guarded　hot　ring　method　(with　annulus　cell　made　of　two　concentric　cylinders),　modified　hot-wire　method　or　forced　Rayleigh　scattering　method.　A　selected　thermal　conductivity　dataset　obtained　using　these　techniques　shows　the　same　temperature　dependence　predicted　by　the　theoretical　model　given　in　the　present　paper.