Akermanite Kusaka K, Hagiya K, Ohmasa M, Okano Y, Mukai M, Iishi K, Haga N Physics and Chemistry of Minerals 28 (2001) 150-166 Determination of structures of Ca2CoSi2O7, Ca2MgSi2O7, and Ca2(Mg.55Fe.45)Si2O7 in incommensurate and normal phases and observation of diffuse streaks at high temperature Sample: T = 359.7 K Melilite group _database_code_amcsd 0008520 7.8398 7.8398 5.0058 90 90 90 P-42_1m atom x y z Biso Mg 0 0 0 .63 Ca .33219 .16781 .5059 1.18 Si .1398 .3602 .9338 .52 O1 0 .5 .819 1.5 O2 .1404 .3596 .2546 1.39 O3 .0826 .1863 .7871 1.42