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AssigneeThe United States of America as represented by the Secretary of the Navy
InventorsIrwin Schneider, William C. Collins, Oscar Imber, Philipp H. Klein
Estimating the term…
The improvement of the electrolytic and additive methods of coloring alkali fluoride crystals comprising the step of selecting an alkali fluoride crystal having the impurities of between 0 and 5 ppmA of OH; between 0 and 50 ppmA of one or more alkaline earth cations, of which between 0 and 10 ppmA Mg.sup.++ and between 0 and 10 ppmA Ca.sup.++ ; between 0 and 50 ppmA of non-fluorine halide anions; between 0 and 10 ppmA of SiF.sub.6.sup.= ; between 0 and 30 ppmA of other ions; and the method of preparing these crystals which comprises converting the alkali fluoride to alkali hydrofluoride, crystallizing and vacuum drying the alkali hydrofluoride crystals, regenerating the alkali fluoride by expelling hydrogen fluoride, and crystallizing the alkali fluoride.
An alkali fluoride crystal consisting essentially of OH.sup.- in an amount from greater than 0 to about 0.5 ppmA, one or more alkaline earth cations in an amount between 0 and 50 ppmA, non-fluoride halide anions in an amount between 0 and 50 ppmA, SiF.sub.6.sup.= in an amount between 0 and 10 ppmA, other ions in an amount between
An alkali metal fluoride crystal selected from the class consisting of lithium fluoride, sodium fluoride, potassium fluoride, and rubidium fluoride prepared by a method which comprises:
Dependencies are inferred from the claim text.