configurations should be equally occupied; this is consistent with our observation that the refined temperature parameters for the alternative methylene sites are very nearly equal. For type ii, which lies on the 2 site, there is evidence from the thermal parameters that the two configurations may not be equally occupied. I n the absence of crystal forces, type ii represents a more energetically favorable state for the tetra-

ethylammonium ion than type i, in that the average distance between methyl groups is the greater.

Acknowledgments: -We wish to thank Ilr. E'. I