data_global _amcsd_formula_title 'Nb2 O7 Tl2' loop_ _publ_author_name 'Fourquet J' 'Duroy H' 'Lacorre P' _journal_name_full 'Journal of Solid State Chemistry' _journal_volume 114 _journal_year 1995 _journal_page_first 575 _journal_page_last 584 _publ_section_title ; Tl2 Nb2 O6+x (0