{"title":"在某些情况下,电气石的[6]协调地点是否部分空置?","authors":"Andreas Ertl","doi":"10.1007/s00710-023-00815-4","DOIUrl":null,"url":null,"abstract":"<div><p>Tourmaline has two different [6]-coordinated sites, the Y site and the Z site. Vacancies were reported from both sites. Based on high-quality chemical and single-crystal structural data it usually needs increasing proportions of short-range order configurations Na(Al<sub>2</sub><b>□</b>)Al<sub>6</sub>(BO<sub>3</sub>)<sub>3</sub>[Si<sub>6</sub>O<sub>18</sub>]<sup>V</sup>(OH)<sub>3</sub><sup>W</sup>(OH) or Na(Al<sub>2</sub><b>□</b>)Al<sub>6</sub>(BO<sub>3</sub>)<sub>3</sub>[Si<sub>6</sub>O<sub>18</sub>]<sup>V</sup>(OH)<sub>3</sub><sup>W</sup>F in order to produce Y-site vacancies (with <b>□</b> being the symbol for a vacant site). Less commonly, the short-range configuration Ca(Al<sub>2</sub><b>□</b>)Al<sub>6</sub>(BO<sub>3</sub>)<sub>3</sub>[Si<sub>5</sub>T<sup>3+</sup>O<sub>18</sub>]<sup>V</sup>(OH)<sub>3</sub><sup>W</sup>(OH) could occur in Al-rich tourmalines with a Si deficiency, where T<sup>3+</sup> = B, Al. Therefore, tourmalines enriched in cations with charge 2 + (Fe<sup>2+</sup>, Mn<sup>2+</sup>, Mg) contain only insignificant Y-site vacancies. Aluminum-rich tourmalines with ≥ 7.0 apfu Al<sub>total</sub> that usually contain ≥ 0.2 apfu Li may have significant vacancies at the Y site. However, no more than 12% vacancies (0.36 pfu) at the Y site can be observed in such samples. If no chemical data for Li is available it is proposed to calculate the Li content in such colourless or coloured tourmalines (elbaite, fluor-elbaite, fluor-liddicoatite, rossmanite) for Y = 2.8 apfu or for Y + Z + T = 14.8 apfu, because this calculation should give more accurate results than calculating the Li content as the difference to 3.0 apfu at the Y site. For Fe<sup>2+</sup>-rich and Mg-bearing tourmalines from the schorl-dravite series with MgO > 1.0 wt% (and only minor amounts of Fe<sup>3+</sup>, Cr<sup>3+</sup> and V<sup>3+</sup>) the structural formula can still be calculated for Y + Z + T = 15 apfu, because such tourmalines do not appear to contain significant Y-site vacancies. It can further be concluded that the Z site could be only ≤ 1% vacant and therefore such vacancies would be insignificant even in Al-rich tourmaline.</p></div>","PeriodicalId":18547,"journal":{"name":"Mineralogy and Petrology","volume":"117 2","pages":"201 - 207"},"PeriodicalIF":1.4000,"publicationDate":"2023-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00710-023-00815-4.pdf","citationCount":"0","resultStr":"{\"title\":\"Are the [6]-coordinated sites in tourmaline in certain cases partially vacant?\",\"authors\":\"Andreas Ertl\",\"doi\":\"10.1007/s00710-023-00815-4\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Tourmaline has two different [6]-coordinated sites, the Y site and the Z site. Vacancies were reported from both sites. Based on high-quality chemical and single-crystal structural data it usually needs increasing proportions of short-range order configurations Na(Al<sub>2</sub><b>□</b>)Al<sub>6</sub>(BO<sub>3</sub>)<sub>3</sub>[Si<sub>6</sub>O<sub>18</sub>]<sup>V</sup>(OH)<sub>3</sub><sup>W</sup>(OH) or Na(Al<sub>2</sub><b>□</b>)Al<sub>6</sub>(BO<sub>3</sub>)<sub>3</sub>[Si<sub>6</sub>O<sub>18</sub>]<sup>V</sup>(OH)<sub>3</sub><sup>W</sup>F in order to produce Y-site vacancies (with <b>□</b> being the symbol for a vacant site). Less commonly, the short-range configuration Ca(Al<sub>2</sub><b>□</b>)Al<sub>6</sub>(BO<sub>3</sub>)<sub>3</sub>[Si<sub>5</sub>T<sup>3+</sup>O<sub>18</sub>]<sup>V</sup>(OH)<sub>3</sub><sup>W</sup>(OH) could occur in Al-rich tourmalines with a Si deficiency, where T<sup>3+</sup> = B, Al. Therefore, tourmalines enriched in cations with charge 2 + (Fe<sup>2+</sup>, Mn<sup>2+</sup>, Mg) contain only insignificant Y-site vacancies. Aluminum-rich tourmalines with ≥ 7.0 apfu Al<sub>total</sub> that usually contain ≥ 0.2 apfu Li may have significant vacancies at the Y site. However, no more than 12% vacancies (0.36 pfu) at the Y site can be observed in such samples. If no chemical data for Li is available it is proposed to calculate the Li content in such colourless or coloured tourmalines (elbaite, fluor-elbaite, fluor-liddicoatite, rossmanite) for Y = 2.8 apfu or for Y + Z + T = 14.8 apfu, because this calculation should give more accurate results than calculating the Li content as the difference to 3.0 apfu at the Y site. For Fe<sup>2+</sup>-rich and Mg-bearing tourmalines from the schorl-dravite series with MgO > 1.0 wt% (and only minor amounts of Fe<sup>3+</sup>, Cr<sup>3+</sup> and V<sup>3+</sup>) the structural formula can still be calculated for Y + Z + T = 15 apfu, because such tourmalines do not appear to contain significant Y-site vacancies. It can further be concluded that the Z site could be only ≤ 1% vacant and therefore such vacancies would be insignificant even in Al-rich tourmaline.</p></div>\",\"PeriodicalId\":18547,\"journal\":{\"name\":\"Mineralogy and Petrology\",\"volume\":\"117 2\",\"pages\":\"201 - 207\"},\"PeriodicalIF\":1.4000,\"publicationDate\":\"2023-02-22\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://link.springer.com/content/pdf/10.1007/s00710-023-00815-4.pdf\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Mineralogy and Petrology\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://link.springer.com/article/10.1007/s00710-023-00815-4\",\"RegionNum\":4,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"GEOCHEMISTRY & GEOPHYSICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Mineralogy and Petrology","FirstCategoryId":"89","ListUrlMain":"https://link.springer.com/article/10.1007/s00710-023-00815-4","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"GEOCHEMISTRY & GEOPHYSICS","Score":null,"Total":0}
引用次数: 0
摘要
碧玺有两个不同的[6]协调位点,Y位点和Z位点。两个地点都报告了空缺。根据高质量的化学和单晶结构数据,通常需要增加短程有序构型Na(Al2□)Al6(BO3)3[Si6O18]V(OH)3W(OH)或Na(Al2□)Al6(BO3)3[Si6O18]V(OH)3WF的比例,以产生y位空位(□是空位的符号)。不太常见的是,富Al (Al2□)Al6(BO3)3[Si5T3+O18]V(OH)3W(OH)的短程构型可能出现在缺Si的富Al电气石中,其中T3+ = B, Al。因此,富含2+电荷的电气石(Fe2+, Mn2+, Mg)只含有不明显的y位空位。总apfu≥7.0的富铝电气石,通常含有≥0.2 apfu Li,可能在Y位点有明显的空位。然而,在这些样品中,在Y位点可以观察到不超过12%的空位(0.36 pfu)。如果没有关于锂的化学数据,建议在Y = 2.8 apfu或Y + Z + T = 14.8 apfu时计算无色或有色电气石(铁榴石、氟铁榴石、氟橄榄石、铁榴石)中的锂含量,因为这种计算应该比在Y点计算锂含量与3.0 apfu的差值更准确。对于MgO > 1.0 wt%(少量Fe3+、Cr3+和V3+)的富Fe2+和含镁电气石,仍然可以计算出Y + Z + T = 15 apfu的结构公式,因为这样的电气石似乎没有明显的Y位空位。可以进一步得出结论,Z位只能有≤1%的空位,因此即使在富al电气石中,这种空位也微不足道。
Are the [6]-coordinated sites in tourmaline in certain cases partially vacant?
Tourmaline has two different [6]-coordinated sites, the Y site and the Z site. Vacancies were reported from both sites. Based on high-quality chemical and single-crystal structural data it usually needs increasing proportions of short-range order configurations Na(Al2□)Al6(BO3)3[Si6O18]V(OH)3W(OH) or Na(Al2□)Al6(BO3)3[Si6O18]V(OH)3WF in order to produce Y-site vacancies (with □ being the symbol for a vacant site). Less commonly, the short-range configuration Ca(Al2□)Al6(BO3)3[Si5T3+O18]V(OH)3W(OH) could occur in Al-rich tourmalines with a Si deficiency, where T3+ = B, Al. Therefore, tourmalines enriched in cations with charge 2 + (Fe2+, Mn2+, Mg) contain only insignificant Y-site vacancies. Aluminum-rich tourmalines with ≥ 7.0 apfu Altotal that usually contain ≥ 0.2 apfu Li may have significant vacancies at the Y site. However, no more than 12% vacancies (0.36 pfu) at the Y site can be observed in such samples. If no chemical data for Li is available it is proposed to calculate the Li content in such colourless or coloured tourmalines (elbaite, fluor-elbaite, fluor-liddicoatite, rossmanite) for Y = 2.8 apfu or for Y + Z + T = 14.8 apfu, because this calculation should give more accurate results than calculating the Li content as the difference to 3.0 apfu at the Y site. For Fe2+-rich and Mg-bearing tourmalines from the schorl-dravite series with MgO > 1.0 wt% (and only minor amounts of Fe3+, Cr3+ and V3+) the structural formula can still be calculated for Y + Z + T = 15 apfu, because such tourmalines do not appear to contain significant Y-site vacancies. It can further be concluded that the Z site could be only ≤ 1% vacant and therefore such vacancies would be insignificant even in Al-rich tourmaline.
期刊介绍:
Mineralogy and Petrology welcomes manuscripts from the classical fields of mineralogy, igneous and metamorphic petrology, geochemistry, crystallography, as well as their applications in academic experimentation and research, materials science and engineering, for technology, industry, environment, or society. The journal strongly promotes cross-fertilization among Earth-scientific and applied materials-oriented disciplines. Purely descriptive manuscripts on regional topics will not be considered.
Mineralogy and Petrology was founded in 1872 by Gustav Tschermak as "Mineralogische und Petrographische Mittheilungen". It is one of Europe''s oldest geoscience journals. Former editors include outstanding names such as Gustav Tschermak, Friedrich Becke, Felix Machatschki, Josef Zemann, and Eugen F. Stumpfl.