Bararite Mineral Data

Bararite Mineral Data +

General Bararite Information

Chemical Formula:

(NH4)2SiF6

Composition:

Molecular Weight = 178.15 gm

Silicon 15.76 % Si 33.73 % SiO₂

Hydrogen 4.53 % H - % Calc as (NH₄)₂O

Nitrogen 15.72 % N 29.23 % (NH₄)₂O

Fluorine 63.98 % F 63.98 % F

- % F -26.94 % -O=F₂

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

(NH₄)₂SiF₆

IMA Status:

Valid Species (Pre-IMA) 1951

Locality:

Link to MinDat.org Location Data.

Synonym:

ICSD 18027

PDF 44-1424

Bararite Image

Images:

Bararite Cryptohalite

Comments: White crystalline bararite intermixed with cryptohalite colored yellow by selenium.
Location: Shamokin, Northumberland County, Pennsylvani, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Bararite Crystallography

Axial Ratios:

a:c = 1:0.82812

Cell Dimensions:

a = 5.76, c = 4.77, Z = 1; V = 137.05 Den(Calc)= 2.16

Crystal System:

Trigonal - Hexagonal ScalenohedralH-M Symbol (3 2/m) Space Group: R 3m

Physical Properties of Bararite

Cleavage:

[0001] Perfect

Color:

White.

Density:

2.152

Hardness:

2.5 - Finger Nail

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Bararite

Gladstone-Dale:

CI meas= -0.848 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.841 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1845,KPDmeas= 0.1852,KC= 0.1002

Optical Data:

Uniaxial (-), e=1.391, w=1.406, bire=0.0150.

Calculated Properties of Bararite

Electron Density:

r_electron=2.18 gm/cc
note: r_Bararite=2.16 gm/cc.

Fermion Index

Fermion Index = 0.16403
Boson Index = 0.83597

Photoelectric:

PE_Bararite= 0.97 barns/electron
U=PE_Bararite x r_electron= 2.12 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Bararite is Not Radioactive

Bararite Classification

Dana Class:

11.5.2.2 (11)Halide Complexes; Alumino-fluorides

(11.5)where (A)m B (X)6

(11.5.2)Dana Group

11.5.2.1 Malladrite Na2SiF6 P 3₂1 3 2

11.5.2.2 Bararite (NH4)2SiF6 R 3m 3 2/m

Strunz Class:

III/B.02-40 III - Halogenides

III/B - Double halogenides without water, with [BF4]1-,[SiF6]2- and [AlF6]3-

III/B.02 - Mallardite - Bararite series

III/B.02-10 Malladrite Na2SiF6 P 3₂1 3 2

III/B.02-20 Hieratite K2SiF6 F m3m 4/m 3 2/m

III/B.02-30 Cryptohalite (NH4)2SiF6 F m3m 4/m 3 2/m

III/B.02-40 Bararite (NH4)2SiF6 R 3m 3 2/m

Other Bararite Information

References:

PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Bararite :
1 -Am. Min. Crystal Structure Database 2 -Athena 3 - EUROmin Project 4 -Google Images 5 -Google Scholar 6 -Handbook of Mineralogy (UofA) 7 -MinDAT 8 -MinMax(Deutsch) 9 -MinMax(English) 10 -Mineralienatlas (Deutsch) 11 -QUT Mineral Atlas 12 -École des Mines de Paris

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Print or Cut-and-Paste your Bararite Specimen Label here :

Bararite

(NH4)2SiF6
Dana No: 11.5.2.2 Strunz No: III/B.02-40
Locality:

Notes: