Ianbruceite, ideally [Zn<sub>2</sub>(OH)(H<sub>2</sub>O)(AsO<sub>4</sub>)](H<sub>2</sub>O)<sub>2</sub>, a new arsenate mineral from the Tsumeb mine, Otjikoto (Oshikoto) region, Namibia: description and crystal structure
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
Abstract Ianbruceite, ideally [Zn 2 (OH)(H 2 O)(AsO 4 )](H 2 O) 2 , is a new supergene mineral from the Tsumeb mine, Otjikoto (Oshikoto) region, Namibia. It occurs as thin platy crystals up to 80 μm long and a few μm thick, which form flattened aggregates up to 0.10 mm across, and ellipsoidal aggregates up to 0.5 mm across. It is associated with coarse white leiteite, dark blue köttigite, minor legrandite and adamite. Ianbruceite is sky blue to very pale blue with a white streak and a vitreous lustre; it does not fluoresce under ultraviolet light. It has perfect cleavage parallel to (100), is flexible, and deforms plastically. The Mohs hardness is 1 and the calculated density is 3.197 g cm -3 . The refractive indices are α = 1.601, β = 1.660, γ = 1.662, all ±0.002; 2V obs = 18(2)°, 2V calc = 20°, and the dispersion is r < v , weak. Ianbruceite is monoclinic, space group P 2 1 / c, a = 11.793(2), b = 9.1138(14), c = 6.8265(10) Å, β = 103.859(9)°, V = 712.3(3) Å 3 , Z = 4, a:b:c = 1.2940:1:0.7490. The seven strongest lines in the X-ray powder diffraction pattern [ d (Å), I , ( hkl )] are as follows: 11.29, 100, (100); 2.922, 17, (130); 3.143, 15, (202); 3.744, 11, (300); 2.655, 9, (230); 1.598, 8, (152); 2.252, 7, (222). Chemical analysis by electron microprobe gave As 2 O 5 36.27, As 2 O 3 1.26, Al 2 O 3 0.37, ZnO 49.72, MnO 0.32, FeO 0.71, K 2 O 0.25, H 2 O calc 19.89, sum 108.79 wt.%; the very high oxide sum is due to the fact that the calculated H 2 O content is determined from crystal-structure analysis, but H 2 O is lost under vacuum in the electron microprobe. The crystal structure of ianbruceite was solved by direct methods and refined to an R 1 index of 8.6%. The As is tetrahedrally coordinated by four O anions with a mean As O distance of 1.687 Å. Zigzag [ [5] Zn [6] Znϕ 7 ] chains extend in the c direction and are linked in the b direction by sharing corners with (AsO 4 ) tetrahedra to form slabs with a composition [Zn 2 (OH)(H 2 O)(AsO 4 )]. The space between these slabs is filled with disordered (H 2 O) groups and minor lone-pair stereoactive As 3+ . The ideal formula derived from chemical analysis and crystal-structure solution and refinement is [Zn 2 (OH)(H 2 O)(AsO 4 )](H 2 O) 2 .
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.001 |
| Meta-epidemiology (narrow) | 0.004 | 0.003 |
| Meta-epidemiology (broad) | 0.003 | 0.001 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.002 | 0.002 |
| Scholarly communication | 0.002 | 0.003 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.002 | 0.003 |
| Insufficient payload (model declined to judge) | 0.000 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it