Increased Compressibility of Pseudobrookite-Type MgTi2O5 Caused by Cation Disorder

+ See all authors and affiliations

Science  26 Sep 1997:
Vol. 277, Issue 5334, pp. 1965-1967
DOI: 10.1126/science.277.5334.1965

You are currently viewing the abstract.

View Full Text


Compressibilities were determined for four pseudobrookite-type magnesium titanate (MgTi2O5) samples with different degrees of Mg-Ti disorder. Compressibilities ofa and c axes in disordered MgTi2O5 were 10% and 7% greater, respectively, than those of a relatively ordered sample. The estimated bulk moduli for fully ordered and disordered MgTi2O5 are 167 ± 1 and 158 ± 1 gigapascals, respectively. This difference is an order of magnitude greater than that predicted by bulk modulus–volume systematics. Cation order, in addition to composition and structure information, is thus important when documenting the elasticity of crystalline phases. Elastic constants of mantle silicates that are subject to pressure-induced cation ordering must be reevaluated.

  • * To whom correspondence should be addressed. E-mail: hazen{at}

View Full Text

Related Content