Lithium fluoride, optical properties

The elements have remarkably low specific gravity, and a high atomic volume (q.v.). The oxides and hydroxides are markedly basic they do not exhibit acidic qualities. The physical properties of the salts—solubility in water, molecular volume, optical properties, and the variation in the form of the crystals show the same order of variation as the atomic weights of the elements. Lithium differs in mafiy respects from the other members of the family. The salts of the alkali metals —nitrates, chlorides, sulphides, sulphates, phosphates, carbonates, etc.—are nearly all soluble in water, although lithium, carbonate, phosphate, and fluoride are very... 

In this section we describe the influence of ionic and polar bonding on structural and optical properties of Na Fm and Li Hm. Since sodium fluorides and lithium hydrides have ionic bulk structures but F and H atoms have very different electron affinities (3.4 and 0.75 eV, respectively), two aspects will be addressed. First, differences and similarities among their properties will be pointed out and second, it will be discussed to what extent these systems possess specific features different from those of the common bulk material. 

The optically transparent liquid-salt coolant is a mixture of fluoride salts with freezing points near 400°C and atmospheric boiling points of 1400 C. The reactor operates at near-atmospheric pressure, and at operating conditions, the liquid-salt heat-transfer properties are similar to those of water. Several different salts can be used as the primary coolant, including lithium-beryllium, sodium-beryllium, and sodium-zirconium fluoride salts. 

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