Redefinition of beraunite, Fe3+6(PO4)4O(OH)4.6H2O, and discreditation of the name eleonorite: a re-investigation of type material from the Hrbek Mine (Czech Republic)

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00023272%3A_____%2F22%3A10135663" target="_blank" >RIV/00023272:_____/22:10135663 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/00216224:14310/22:00125673

Výsledek na webu

<a href="https://ejm.copernicus.org/articles/34/223/2022/" target="_blank" >https://ejm.copernicus.org/articles/34/223/2022/</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.5194/ejm-34-223-2022" target="_blank" >10.5194/ejm-34-223-2022</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Redefinition of beraunite, Fe3+6(PO4)4O(OH)4.6H2O, and discreditation of the name eleonorite: a re-investigation of type material from the Hrbek Mine (Czech Republic)

Popis výsledku v původním jazyce

Re-investigation of the type material of beraunite from the Hrbek Mine, Svatá Dobrotivá, Czech Republic, proved the identity of beraunite and eleonorite. Based on this study, the mineral eleonorite was discredited and the ideal formula of beraunite was redefined from Fe2+Fe3+5(PO4)4(OH)5.6H2O to Fe3+6(PO4)4O(OH)4.6H2O. Beraunite from Hrbek Mine usually forms prismatic crystals (flattened on {100}; elongated along b axis, striated on {100} || b, up to 0.2 x 0.5 x 3 mm, often in radial clusters up to 6 mm in size in association with black goethite, olive-green to dark green dufrénite and yellow to orange cacoxenite. Beraunite is hyacinth-red, dark red or red-brown and has a light orange-red streak; crystals are translucent, with a vitreous lustre. The symmetry of the structure was found to be lower (Cc) than reported in the past (C2/c), this has been proven by the crystal structure refinement, Robs = 2.7% for Cc and ~8% for C2/m. Unit-cell parameters of original material of F. A. Breithaupt derived from powder X-ray diffraction data are: a = 20.653(2), b = 5.1433(6), c = 19.241(2) Å, β = 93.560(9)o and V = 2039.9(2) Å3. Calculated density is 2.961 g.cm-3. Beraunite is optically biaxial (+), α = 1.768(2), β = 1.781(3), γ &gt; 1.805, 2Vmeas = 69(4)o, 2Vcalc = not possible to calculate. Dispersion of optical axes is strong, r &gt; v. The orientation is Y = b; X ALMOST EQUAL TO a, and Z ALMOST EQUAL TO c. The empirical formula of the original beraunite sample calculated on the basis of P = 4 apfu is: Fe3+5.76Al0.15Zn0.01(PO4)4.00O0.99(OH)3.77.6H2O. 57Fe Mössbauer spectrum of beraunite neotype (National Museum, Prague) from type locality implies that all iron atoms in beraunite structure are exclusively trivalent, located at M site with different next-nearest neighbour configurations. There is no spectral evidence for Fe2+ or iron in some impurities (e.g., limonite).

Název v anglickém jazyce

Redefinition of beraunite, Fe3+6(PO4)4O(OH)4.6H2O, and discreditation of the name eleonorite: a re-investigation of type material from the Hrbek Mine (Czech Republic)

Popis výsledku anglicky

Re-investigation of the type material of beraunite from the Hrbek Mine, Svatá Dobrotivá, Czech Republic, proved the identity of beraunite and eleonorite. Based on this study, the mineral eleonorite was discredited and the ideal formula of beraunite was redefined from Fe2+Fe3+5(PO4)4(OH)5.6H2O to Fe3+6(PO4)4O(OH)4.6H2O. Beraunite from Hrbek Mine usually forms prismatic crystals (flattened on {100}; elongated along b axis, striated on {100} || b, up to 0.2 x 0.5 x 3 mm, often in radial clusters up to 6 mm in size in association with black goethite, olive-green to dark green dufrénite and yellow to orange cacoxenite. Beraunite is hyacinth-red, dark red or red-brown and has a light orange-red streak; crystals are translucent, with a vitreous lustre. The symmetry of the structure was found to be lower (Cc) than reported in the past (C2/c), this has been proven by the crystal structure refinement, Robs = 2.7% for Cc and ~8% for C2/m. Unit-cell parameters of original material of F. A. Breithaupt derived from powder X-ray diffraction data are: a = 20.653(2), b = 5.1433(6), c = 19.241(2) Å, β = 93.560(9)o and V = 2039.9(2) Å3. Calculated density is 2.961 g.cm-3. Beraunite is optically biaxial (+), α = 1.768(2), β = 1.781(3), γ &gt; 1.805, 2Vmeas = 69(4)o, 2Vcalc = not possible to calculate. Dispersion of optical axes is strong, r &gt; v. The orientation is Y = b; X ALMOST EQUAL TO a, and Z ALMOST EQUAL TO c. The empirical formula of the original beraunite sample calculated on the basis of P = 4 apfu is: Fe3+5.76Al0.15Zn0.01(PO4)4.00O0.99(OH)3.77.6H2O. 57Fe Mössbauer spectrum of beraunite neotype (National Museum, Prague) from type locality implies that all iron atoms in beraunite structure are exclusively trivalent, located at M site with different next-nearest neighbour configurations. There is no spectral evidence for Fe2+ or iron in some impurities (e.g., limonite).

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10504 - Mineralogy

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2022

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

European Journal of Mineralogy

ISSN

0935-1221

e-ISSN

—

Svazek periodika

34

Číslo periodika v rámci svazku

2

Stát vydavatele periodika

DE - Spolková republika Německo

Počet stran výsledku

16

Strana od-do

223-238

Kód UT WoS článku

000780842500001

EID výsledku v databázi Scopus

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