Potassium, K


Technical Data
Symbol K Melting point /°C 63.2
Atomic number 19 Boiling point /°C 765.5
No. of naturally occurring isotopes 2+1* ΔHfus/kJmol-1 2.39
Atomic weight 39.0983 ΔHvap/kJmol-1 79
Electronic configuration [Ar]4s1 ΔHf(monoatomic gas)/kJmol-1 90
Metal radius/pm 227 ΔH(dissoc)/kJmol-1 49.9
Ionic radius(6-coordinate)/pm 138 Ionization energy/kJmol-1 418.6
Eo(M+(aq)+e- →M(S))/V -2.925 *(radioactive 4°K t1/2 1.27 x 109 y)  
Density (20°C)/gcm3 0.856    
Evaporation Techniques
Temperature (oC) @Vap. Pressure Techniques Remarks
842 992 1192 Excellent Al2O3 Tungsten Tungsten Alloys with refractory metals; rapid Evaporation suggested. Spits in EB.

Evaporation Materials
P4-5000-M small pieces