Single crystals of stannic oxide up to 30×4×2 mm have been prepared by a high temperature vapor deposition technique. Using high purity SnO2 powder, crystallization and growth were studied under both neutral and oxidizing conditions. Neutral carrier gases, with the exception of helium, encouraged the formation of voids and inclusions. However, the use of a helium-oxygen system was found to eliminate these defects. An explanation is offered for this behavior. Three distinct variations in the crystalline habit of SnO2 have been observed, apparently dependent upon the temperature at which growth occurred.

Mhen govermnt or other drawings, specifications or other data are used for any purlpose other than in connection with a definitely related government procurmnt operation, the U. S. Govenmnt thereby Incurs no responsibility, nor any obligstion whatsoever; and the fact that the Government my have formuflated, furnished, or In any way supplied the said drawings, specifications, or other data Is not to be regarded by imiplication or otherwise as in any manner licensing the holder or any other person or corporation,, or conveying amy rights or permission to manufacture, use or sell mny patented invention that =y in any way be related thereto.