Neutron Diffraction Study on the Structure of Liquid Cs-Sb Alloys

Abstract By neutron diffraction experiments the total structure factors and the total pair correlation functions of liquid Cs-Sb alloys containing 85, 75, 65, and 50 at% Cs, respectively, were determined. The structural results confirm the non metallic properties of Cs-Sb melts. The correspondence of the nearest neighbour atomic arrangement in liquid Cs75Sb25 and in the solid compound semiconductor Cs3Sb suggests a similar type of bonding, namely by valence bonds and ionic forces simultaneously. The stability of this compound in the molten state leads to a microsegregation tendency between compound forming regions and excess Cs in the concentration range from pure Cs up to 25 at% Sb, which is established by a small angle scattering effect. Proceeding from Cs75Sb25 to Cs50Sb50, a continuous change in the structure takes place. Covalently bonded Sb chains are formed just as found in the corresponding solid compounds ASb (A = alkali metal). An additional diffraction peak in front of the main peak of the structure factors within this composition range implies the formation of rather large molecular clusters in the alloys.