D.A.K.); igorpekov@mail.ru (I.V.P.); art4anya@ya.ru (A.A.A.); Abstract: The crystal structure of the Ag-exchanged form of the zirconosilicate with the simplified formula (Na 6-2x Ca x x )Zr 3 [Si 9 O 27 ] with x < 1 (the idealized formula Na 6 Zr 3 [Si 9 O 27 ]), a product of thermal transformation of catapleiite, ideally Na 2 Zr[Si 3 O 9 ]·2H 2 O, was studied using single crystal X-ray diffraction data. The crystal structure of Na 6 Zr 3 [Si 9 O 27 ] is based on a heteropolyhedral framework built by nine-membered tetrahedral rings [Si 9 O 27 ] and isolated [ZrO 6 ] octahedra. This zirconosilicate demonstrates high exchange capacity to Ag (experiment with 1 M AgNO 3 aqueous solution, 250 • C, 30 days). Its Ag-exchanged form with the simplified formula (Ag 5 Ca 0.5 )Zr 3 [Si 9 O 27 ] is characterized by a significant distortion of the heteropolyhedral framework and strongly disordered arrangement of extra-framework cations (Ag) which results in the doubling of a parameter of the hexagonal unit cell [a = 23.3462(3), c = 10.10640(10) Å, V = 4770.45(13) Å 3 ] and space group P6 3 cm. Ag + cations preferably occupy the sites that are close to the Na sites in Na 6 Zr 3 [Si 9 O 27 ].
The presented clinical observation and analysis of the literature data draws an attention on the possibility of developing a life-threatening condition such as methemoglobinemia due to the use of the benzocaine preparation. The latter is part of the preparation bellastesin for the treatment of gastroenterological diseases. This drug is often taken by patients at their own at discretion and with no proper control and consideration of existing co-morbidities. In addition, one needs to pay attention on the indicators of oximetry, including the level of methemoglobin, when diagnosing diseases accompanied by cyanosis and respiratory insufficiency.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.