A refinement of the crystal structure of ohmilite, Sr 3 (Ti,Fe (super 3+) )(O,OH)(Si 2 O 6 ) 2 . 2-3H 2 O

A = 10.979(6), b = 7.799(5), c = 7.818(4) angstrom, beta = 100.90(3) degrees , and space group P2 1 /m; Z = 2, V = 657.4(6) angstrom 3 . Each of the octahedral chains is flanked by a pair of [Si 4 O 12 ] chains, which are similar to those found in batisite and haradaite, thus forming a composite chain of composition [Si 4 O 12 (Ti 2 O 2 )Si 4 O 12 ] (super 12-) . These composite chains are joined together by Sr atoms and water molecules. Hydrogen is present as both H 2 O and OH.--Modified journal abstract.