Reference:
▪ Sapozhnikov, A.N., Kaneva, E.P., Surorova, L.P., Levitsky, V.I., Ivanova, L.A. (2017): Sulfhydrylbystrite, Na5K2Ca(Al6Si6O24)(S5)(SH), a new mineral with the LOS framework, and re-interpretation of bystrite: cancrinite-group minerals with novel extra-framework anions. Mineralogical Magazine, 81, 383–402.
Abstract:
Sulfhydrylbystrite, Na5K2Ca(Al6Si6O24)(S5)(SH), cell parameters a = 12.9567(6) Å, c = 10.7711(5) Å, space group P31c, is a new mineral belonging to the cancrinite group. It was found at Malaya Bystraya lazurite deposit, Lake Baikal area, Eastern Siberian Region, Russia, associated with lazurite, calcite, diopside, phlogopite and pyrite. The mineral develops at the margins of masses of lazurite, replacing it in some areas with the formation of nonequilibrium lazurite-diopside-sulfhydrylbystrite association. It is translucent, yellow to orange, with vitreous lustre, yellow streak and Mohs’ hardness of 4.5 - 5. The empirical formula, based on 12 (Si + Al), is Na5.17K1.87Ca0.99[Al6.01Si5.99O24](S5)2- 0.86(SH0.86)Cl0.07, Z=2. The crystal structure of sulfhydrylbystrite may be described as an ABAC stacking of six-membered rings of 23 SiO4 and AlO4 tetrahedra and extra-framework cations and anions located within structural cages. There are two type of cages, cancrinite and losod, stacked into chains at at (0, 0, z) and (⅔, ⅓, z), respectively. The cancrinite cage hosts Ca2+ and (SH)- ions, whereas (S5)2- polyanion is in the losod cage associated with Na+ and K+ cations. In addition, (SH)- and (S5)2- anions are for the first time detected in the structure of a mineral. For comparison, a structural and compositional study of bystrite sample from the same deposit was carried out. Bystrite is confirmed to contain pentasulfide anions in the losod cages, similar to those of sulfhydrylbystrite, in contrast to previous studies. However, bystrite has chloride in cancrinite cages, whereas sulfhydrylbystrite has hydrosulfide in that position. The unit cell parameters are distinctly different: bystrite has a = 12.8527(6) Å, c = 10.6907(5) Å in the same P31c space group.
▪ Sapozhnikov, A.N., Kaneva, E.P., Surorova, L.P., Levitsky, V.I., Ivanova, L.A. (2017): Sulfhydrylbystrite, Na5K2Ca(Al6Si6O24)(S5)(SH), a new mineral with the LOS framework, and re-interpretation of bystrite: cancrinite-group minerals with novel extra-framework anions. Mineralogical Magazine, 81, 383–402.
Abstract:
Sulfhydrylbystrite, Na5K2Ca(Al6Si6O24)(S5)(SH), cell parameters a = 12.9567(6) Å, c = 10.7711(5) Å, space group P31c, is a new mineral belonging to the cancrinite group. It was found at Malaya Bystraya lazurite deposit, Lake Baikal area, Eastern Siberian Region, Russia, associated with lazurite, calcite, diopside, phlogopite and pyrite. The mineral develops at the margins of masses of lazurite, replacing it in some areas with the formation of nonequilibrium lazurite-diopside-sulfhydrylbystrite association. It is translucent, yellow to orange, with vitreous lustre, yellow streak and Mohs’ hardness of 4.5 - 5. The empirical formula, based on 12 (Si + Al), is Na5.17K1.87Ca0.99[Al6.01Si5.99O24](S5)2- 0.86(SH0.86)Cl0.07, Z=2. The crystal structure of sulfhydrylbystrite may be described as an ABAC stacking of six-membered rings of 23 SiO4 and AlO4 tetrahedra and extra-framework cations and anions located within structural cages. There are two type of cages, cancrinite and losod, stacked into chains at at (0, 0, z) and (⅔, ⅓, z), respectively. The cancrinite cage hosts Ca2+ and (SH)- ions, whereas (S5)2- polyanion is in the losod cage associated with Na+ and K+ cations. In addition, (SH)- and (S5)2- anions are for the first time detected in the structure of a mineral. For comparison, a structural and compositional study of bystrite sample from the same deposit was carried out. Bystrite is confirmed to contain pentasulfide anions in the losod cages, similar to those of sulfhydrylbystrite, in contrast to previous studies. However, bystrite has chloride in cancrinite cages, whereas sulfhydrylbystrite has hydrosulfide in that position. The unit cell parameters are distinctly different: bystrite has a = 12.8527(6) Å, c = 10.6907(5) Å in the same P31c space group.