{"doi":"10.2113/gscanmin.45.5.1247","title":"FROM STRUCTURE TOPOLOGY TO CHEMICAL COMPOSITION. II. TITANIUM SILICATES: REVISION OF THE CRYSTAL STRUCTURE AND CHEMICAL FORMULA OF DELINDEITE","abstract":null,"journal":"The Canadian Mineralogist","year":2007,"id":636574,"datarank":0.49983067652628066,"base_score":3.332204510175204,"endowment":3.332204510175204,"self_citation_contribution":0.49983067652628066,"citation_network_contribution":0.0,"self_endowment_contribution":0.49983067652628066,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":27,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":null,"is_data_producer":false,"deposit_databanks":null,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":null,"fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1652303,"name":"F. Camara","orcid":null,"position":1,"is_corresponding":false},{"id":1652302,"name":"E. Sokolova","orcid":null,"position":0,"is_corresponding":false}],"reference_count":0,"raw_metadata":{"has_enrichment":true,"resolved":true,"title":"FROM STRUCTURE TOPOLOGY TO CHEMICAL COMPOSITION. II. TITANIUM SILICATES: REVISION OF THE CRYSTAL STRUCTURE AND CHEMICAL FORMULA OF DELINDEITE","abstract":"The crystal structure of delindeite, ideally Ba 2  Na 2  Ti 3  (Si 2 O 7 ) 2  O 2  (OH) 2  (H 2 O) 2 ,  a  10.6452(9),  b  13.713(1),  c  21.600(2) A, β 93.804(3)°,  V  3146.15(5) A 3 , space group  C 2/ c ,  Z  = 8,  D  calc.  3.74 g.cm −3  from Mt. Yuksporr, Khibina alkaline massif, Kola Peninsula, Russia, has been solved by direct methods and refined to an  R  1  value of 6.4% on the basis of 3559 unique reflections ( F  o  ≥ 4σ F ) collected on a Bruker AXS SMART APEX diffractometer with a CCD detector and Mo K α radiation. Electron-microprobe analyses gave (wt.%): SiO 2  27.08, Al 2 O 3  0.29, Nb 2 O 5  1.98, TiO 2  24.33, Fe 2 O 3  1.07, FeO 0.40, MnO 0.19, BaO 33.20, Na 2 O 4.63, K 2 O 1.37, F 1.41, H 2 O 5.29 (calculated from structure refinement), O=F −0.59, total 100.65. The empirical formula is (Ba 1.92  K 0.08 ) ∑2.00  (Na 1.33  K 0.18  Fe 2+  0.05  Mn 2+  0.02  □ 1.42 ) ∑3.00  (Ti 2.70  Fe 3+  0.12  Nb 0.13 Al 0.05 ) ∑3.00  (Si 2 O 7 ) 2  [O 1.53 (OH) 0.47 ] ∑2.00  [(OH) 1.34  F 0.66 ]  ∑2.00  (H 2 O) 1.70 ,  Z  = 8, calculated on the basis of 4 Si ( apfu ). The crystal structure of delindeite can be described as combination of two blocks. The first block consists of HCH sheets (H: heteropolyhedral, C: central), and it is related to the TS (titanium silicate) block in Ti disilicate minerals. In the TS block, there are seven fully occupied cation sites, four [4]-coordinated  Si  sites with   1.622 A and three [6]-coordinated Ti-dominant sites. Two sites,  M (1) and  M (2), are coordinated by five O atoms and one OH group,   1.974 A; they give Ti 1.88 Nb 0.07 Al 0.05 ; the  M (3) site, of composition Ti 0.82 Fe 3+  0.12 Nb 0.06 , is coordinated by four O atoms and two OH groups,   1.964 A. There are four partially occupied sites: the  Na (1) and  Na (2) sites are occupied by Na with minor Fe 2+  and Mn 2+  at 70%,  2 O> 2.31 A; the [8]-coordinated  Na (3) site of composition (Na 0.70 □ 0.30 ,  2 O> 2.52 A), and the [7]-coordinated  K  site of composition (K 0.18 □ 0.82 ,   2.90 A), are at a short distance, 1.25 A. The M(1,2) octahedra and (Si 2 O 7 ) groups constitute the H sheet that is completely ordered. In the C sheet, M(3) octahedra and H 2 O groups [O(19)] are long-range ordered, whereas Na(1–3) and K atoms and three H 2 O groups [O(20–22) with 46, 44 and 50% occupancy] are long-range disordered. Three SRO (short-range order) arrangements have been considered for the C sheet: (1) Na(1), Na(2), 2 Na(3), H 2 O [O(22)]; (2) K; (3) 2 H 2 O [O(20) and O(21)]. Two H 2 O sites [O(20) and O(21)] correspond to two cation sites in the close-packed O sheet of octahedra (O sheet). The substitution H 2 O + 2□↔Na +  + 2O 2−  describes the relation between the composition of the C and O sheets. Linkage of H and C sheets occurs  via  common vertices of M(1,2) octahedra and (Si 2 O 7 ) groups with M(3) octahedra. The second or intermediate  I  block includes the [10]-coordinated  Ba (1) and  Ba (2) sites of composition Ba 0.92 K 0.08  and Ba 1.00 ,   2.961 and   2.873 A. The HCH and  I  block, which is a layer of Ba atoms, alternate along  c . The ideal formula of delindeite is Ba 2  Na 2  Ti 3  (Si 2 O 7 ) 2  O 2  (OH) 2  (H 2 O) 2 ,  Z  = 8. The crystal structure reported here explains why the TS block in delindeite exhibits topology different from that of the titanium disilicate minerals, where the central sheet is trioctahedral.","is_dataset_classified":null,"base_score":3.332204510175204,"endowment":3.332204510175204,"datacite_reuse_total":0,"file_count":0,"downloads":0,"views":0,"has_version_chain":false,"is_dataset":false,"is_oa":false,"pmid":"19767382","pmcid":null,"openalex_id":"https://openalex.org/W2140303593","authors":[],"funders":[],"total_grants":0,"fwci":2.5093,"citation_percentile":0.90023781,"influential_citations":0,"citation_trend":[{"year":2013,"count":2},{"year":2014,"count":1},{"year":2015,"count":1},{"year":2016,"count":2},{"year":2017,"count":2},{"year":2018,"count":1},{"year":2023,"count":1}],"oa_status":"closed","license":null,"oa_locations":[{"url":"https://doi.org/10.2113/gscanmin.45.5.1247","host_type":"journal"}],"fields_of_study":["Crystal Structures and Properties","X-ray Diffraction in Crystallography","Chemical Synthesis and Characterization"],"mesh_terms":[],"keywords":["Titanium","Chemical composition","Topology (electrical circuits)","Crystal structure","Composition (language)","Materials science","Crystallography","Chemistry","Mineralogy","Metallurgy","Mathematics","Combinatorics","Organic chemistry","Art"],"sdg_mappings":[{"sdg_number":0,"sdg_label":"Life below water"}],"linked_datasets":[],"clinical_trials":[],"software_tools":[],"database_accessions":[],"source":"live","citation_network_status":"fetched"},"created_at":"2026-08-06T17:18:41.369269Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}