Hylbrownite

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Hylbrownite
General and classification
other names

IMA2010-054

chemical formula Mg 2+ Na 3 (P 3 O 10 ) • 12H 2 O
Mineral class
(and possibly department) 		Phosphates, arsenates, vanadates
System no. to Strunz
and to Dana 		8.FC. ( 8th edition : 7 / C.37-005)
04/46/01.
Crystallographic Data
Crystal system monoclinic
Crystal class ; symbol monoclinic prismatic; 2 / m
Space group P 2 1 / n (No. 14, position 2)Template: room group / 14.2
Lattice parameters a  = 14.722 (3)  Å ; b  = 9.240 (2) Å; c  = 15.052 (3) Å
α  = 90 °; β  = 90.01 (3) °; γ  = 90 °
Formula units Z  = 4
Frequent crystal faces {010}, {100}, {001}, {210}, {201}
Physical Properties
Mohs hardness not determined
Density (g / cm 3 ) measured: 1.81 (4); calculated: 1.82
Cleavage good after {001} and {100}
Break ; Tenacity uneven
colour colorless
Line color White
transparency transparent
shine Glass gloss
Crystal optics
Refractive indices n α  = 1.390 (4)
n β  = 1.421 (4)
n γ  = 1.446 (4)
Birefringence δ = 0.031-0.056
Optical character biaxial negative
Axis angle 2V = 82.2 ° (calculated)
Pleochroism none

The mineral hylbrownite is a very rare, hydrous triphosphate with the chemical composition Mg 2+ Na 3 (P 3 O 10 ) · 12H 2 O. It crystallizes with monoclinic symmetry and forms white, radial aggregates of colorless, needle-like to hair-like crystals, which are rare become larger than 0.12 mm.

Hylbrownite forms secondary at very low temperatures around 25 ° C and is known so far (2020) only from two sites. The type locality is the Dome Rock copper mine in the Boolcoomatta Reserve in the Olary District in South Australia , ~ 50km west of Broken Hill , Australia .

Etymology and history

The Australian geologist Henry Yorke Lyell Brown around 1900

Compounds of the type M 2+ Na 3 (P 3 O 10 ) · 12H 2 O wherein M 2+ represents divalent cations are known since 1899 at the latest, when Paul Glühmann in his dissertation at the Friedrich-Wilhelms University in Berlin , the Cadmium salt of this type described. The first synthesis and structure determination of the Mg representative of this group was carried out in 1972 by Emile Rakotomahanina-Rolaisoa and co-workers.

Natural polyphosphates were unknown for a long time and it was assumed that they cannot form under geologically relevant conditions until the first natural diphosphate was described in 1983 with canaphite and in 1997 the first natural triphosphate canonerovite .

The dome skirt copper mine was a known source of secondary arsenate in the 1980s and is the type locality of Cobaltaustinit and Domerockit . The handpieces on which the third mineral discovered there, hylbrownite, was found, were probably already collected at this time. Described and recognized as a new mineral, hylbrownite was described by P. Elliott and co-workers at the University of Adelaide nearly 30 years later . They named the new mineral after the state geologist of South Australia, Henry Yorke Lyell Brown (1844-1928), who was one of the first to explore the interior of the state and in 1899 created the first geological map of the colony.

After Kanonerovite, hylbrownite is the second known mineral with a triphosphate anion.

classification

Since hylbrownite was only recognized as an independent mineral in 2010, it is not yet listed in the 8th edition of the mineral classification according to Strunz , which has been outdated since 1977 . Only in the Lapis mineral directory according to Stefan Weiß, which, out of consideration for private collectors and institutional collections, is still based on this old form of Karl Hugo Strunz's system , was the mineral given the system and mineral number. VII / C.37-005 . In the "lapis system" this corresponds to the class of "phosphates, arsenates and vanadates" and there the section "water-containing phosphates, without foreign anions ", where hylbrownite together with canonerovite form the group " anhydrous triphosphates [P 3 O 10 ] 5- "Forms (as of 2018).

The 9th edition of Strunz's mineral systematics, which has been valid since 2001 and was updated by the International Mineralogical Association (IMA) until 2009 , does not yet list hylbrownite. It could be found together with Kanonerovite in group 8.FC.30 in the subsection “Diphosphates etc. with only H 2 O”, section “Polyphosphates, polyarsenates, [4] -Polyvanadates”.

Also in the systematics of minerals according to Dana , which is mainly used in the English-speaking area , the hylbrownite would be classified in the class of "phosphates, arsenates and vanadates" and there in the department of "basic or halogen-containing antimonites, arsenites and phosphites". Here it could be found with Kanonerovite in the unnamed group 46.04.01 within the sub-section "Basic or halogenated antimonites, arsenites and phosphites with (AB) m (XO3) p Zq × x (H2O)".

Chemism

Hylbrownit is the magnesium analog of Kanonerovite and has the simplified composition Mg 2+ Na 3 (P 3 O 10 ) · 12H 2 O. The measured composition of Hylbrownit from the type locality is:

  • (Mg 2+ 0.99 Ca 2+ 0.04 ) (Na 2.93 ) (P 2.99 O 9.97 ) • 12.03H 2 O.

A few other compounds of this type are known synthetically:

  • Cd 2+ Na 3 (P 3 O 10 ) • 12H 2 O
  • Ni 2+ Na 3 (P 3 O 10 ) • 12H 2 O
  • Co 2+ Na 3 (P 3 O 10 ) • 12H 2 O
  • Zn 2+ Na 3 (P 3 O 10 ) • 12H 2 O
  • Mn 2+ Na 3 (P 3 O 10 ) • 12H 2 O
  • Cu 2+ Na 3 (P 3 O 10 ) • 12H 2 O
  • Mg 2+ Na 3 (P 3 O 10 ) • 12H 2 O

Crystal structure

Hylbrownite crystallizes with monoclinic symmetry of the space group P 2 1 / n (space group no. 14, position 2) and 4 formula units per unit cell . The natural hylbrownite from the type locality has the lattice parameters a  = 14.722 (3)  Å , b  = 9.33 (2) Å, c  = 15.13 (1) Å and ß = 89.8 (1). The lattice parameters a  = 14.763 (2)  Å , b  = 9.240 (2) Å, c  = 15.052 (3) Å and ß = 90.01 (3) ° were determined for the pure synthetic equivalent of hylbrownite . Template: room group / 14.2

Phosphorus (P 5+ ) occupies three tetrahedral positions surrounded by 4 oxygen ions. The three tetrahedra are connected to a P 3 O 10 group via common oxygen ions of the PO 4 tetrahedron corners .

Magnesium (Mg 2+ ) is surrounded by three oxygen and three water molecules in the form of a distorted octahedron , with the three oxygens each belonging to one corner of a PO 4 tetrahedron of a P 3 O 10 group.

These [MgP 3 O 10 (H 2 O) 3 ] 3 - complexes are held together by Na + ions and hydrogen bonds .

Sodium (Na + ) sits in three different positions, where it is either octahedrally surrounded by one oxygen and 5 water molecules (Na1, Na3) or one oxygen and 4 water molecules in the form of a strongly distorted square pyramid (Na2). Very weak bonds to an oxygen ~ 3.1 Å away and the oxygen of another water molecule increase the coordination number to 7.


Education and Locations

Hylbrownit separates from phosphate-containing solutions at very low temperatures of 25 ° C or less.

So far (2020) the mineral hylbrownite has only been documented at two locations. The type locality is the Dome Rock copper mine in the Boolcoomatta Reserve in the Olary District in South Australia , ~ 50km west of Broken Hill , Australia . It occurs here in a narrow crack on pale green conichalcite and on crusts of chrysocolla or an amorphous copper-manganese-cobalt-silicate. In a second handpiece in the same location, hylbrownite was found on a quartzite interspersed with iron oxides, together with cuprite , malachite , azurite and goethite . Together with hydroxyapatite , it is the only secondary phosphate at the site. The source of the phosphorus are probably phosphate- containing pegmatites in the vicinity.

The second documented location is a chlorite outcrop in the serpentinites of the Sassi Neri-Sodera area in the municipality of Impruneta in the metropolitan city of Florence in Tuscany , Italy . Hylbrownite is found here in the form of millimeter-sized tufts or radial aggregates on chrysotile .

See also

Web links

Individual evidence

  1. ^ IMA Outreach Committee: mineral list group: IMA Database of Mineral Properties. (HTML) In: rruff.info/ima. RRUFF Project, accessed on May 4, 2020 .
  2. ↑ a b c d e f g h i j k l m n o p q r s t u v w x y z aa P. Elliott, J. Brugger, T. Caradoc-Davies, A. Pring: Hylbrownite, Na3MgP3O10 12H2O, a new triphosphate mineral from the Dome Rock Mine, South Australia: description and crystal structure . In: Mineralogical Magazine . tape 77 , 2013, p. 385–398 ( rruff.info [PDF; 367 kB ; accessed on May 4, 2020]).
  3. ↑ Mineral Atlas: Hylbrownit
  4. ↑ Hylbrownite. In: mindat.org. Hudson Institute of Mineralogy, accessed May 10, 2020 .
  5. ↑ a b c d e Vladimir Lutsko and Georg Johansson: The Crystal structure of trisodium cadmium triphosphate Na3CdP3O10 [H2O] 12 . In: Acta Chemica Scandinavica . A38, 1984, p. 415-417 ( actachemscand.org [PDF; 388 kB ; accessed on April 22, 2020]).
  6. ↑ a b c d e f g h Emile Rakotomahanina-Rolaisoa, Marie-Thérèse Averbuch, André Durif-Varambon: Données cristallographiques sur les triphosphates du type MIINa3P3O10 • 12H2O pour MII = Ni, Co, Mn, Mg, Zn et Cd . In: Bulletin de la Société française deMinéralogie et de Cristallographie . tape 95 , 1972, pp. 516–520 ( persee.fr [PDF; 843 kB ; accessed on April 19, 2020]).
  7. ↑ K. Byrappa: The possible reasons for the absence of condensed phosphates in nature . In: Physics and Chemistry of Minerals . tape 10 , 1983, p. 94-95 , doi : 10.1007 / BF00309591 .
  8. ^ A b Roland C. Rouse, Donald R. Peacor, Robert L. Freed: Pyrophosphate groups in the structure of canaphite, CaNa 2 P 2 O 7 · 4H 2 O: The first occurrence of a condensed phosphate as a mineral . In: American Mineralogist . tape 73 , 1988, pp. 168–171 ( rruff.info [PDF; 448 kB ; accessed on February 10, 2020]).
  9. ^ A b VI Popova, VA Popov, EV Sokolova, G. Ferraris, NV Chukanov: Kanonerovite, MnNa3P3O1012H2O, first triphosphate mineral (Kazennitsa pegmatite, Middle Urals, Russia) . In: New yearbook for mineralogy - monthly books . tape 3 , 2002, p. 117–127 ( researchgate.net [PDF; 224 kB ; accessed on April 19, 2020]).
  10. ↑ Stefan Weiß: The large Lapis mineral directory. All minerals from A - Z and their properties. Status 03/2018 . 7th, completely revised and supplemented edition. Weise, Munich 2018, ISBN 978-3-921656-83-9 .
  11. ↑ Ernest H. Nickel, Monte C. Nichols: IMA / CNMNC List of Minerals 2009. (PDF 1816 kB) In: cnmnc.main.jp. IMA / CNMNC, January 2009, accessed April 8, 2020 .
  12. ↑ a b Khalil Azzaoui, Rachid Essehli, El Miloud Mejdoubi, Brahim El Bali, Michal Dusek and Karla Fejfarova: Na3MP3O1012H2O (M = Co, Ni): Crystal Structure andIR Spectroscopy . In: International Journal of Inorganic Chemistry . tape 2012 , 2012, p. 1–6 ( hindawi.com [PDF; 2.7 MB ; accessed on April 22, 2020]).
  13. ↑ a b c d P. Lightfoot and AK Cheetham: Structure of manganese (II) trisodium tripolyphosphate dodecahydrate . In: Acta Crystallographica . C43, 1987, pp. 4-7 , doi : 10.1107 / S0108270187097221 .
  14. ↑ O. Jouini, M. Dabbabi, MT Averbuch-Pouchot, A. Durif et JC Guitel: Structure du triphosphate de cuivre (II) et de trisodium dodécahydraté, CuNa3P3O10.12H2O . In: Acta Crystallographica . C40, 1984, pp. 728-730 , doi : 10.1107 / S0108270184005503 .
  15. ↑ Find location list for hylbrownite at the Mineralienatlas and at Mindat
  16. ↑ C. Batacchi, M. Capperi, C. Cosci, E. Bittarello, ME Ciriotti, B. Prosperi, G. Borselli, B. Fassina, L. Ceccantini: Secondo ritrovamento mondiale di hylbrownite e altre nuove identificazioni nelle serpentiniti di Impruneta, Toscana. In: Micro . tape 1 , 2015, p. 40–51 ( researchgate.net [PDF; 8.6 MB ; accessed on May 10, 2020]).