Home > Mineral Abstracts > AmMin Vol. 80, pp. 1059-1064 (1995)




Journal of the Mineralogical Society of America

Vol. 80, pp. 1059-1064 (1995)

Reederite-(Y), a new sodium rare-earth carbonate mineral with
a unique fluorosulfate anion

Joel D. Grice, Robert A. Gault
Research Division, Canadian Museum of Nature,
P.O. Box 3443, Station D, Ottawa,
Ontario K1P 6P4, Canada



George Y. Chao
Department of Earth Sciences, Carleton University,
Ottawa, Ontario K1S 5B6, Canada

ABSTRACT

     Reederite-(Y), ideally, (Na,Mn,Fe)15(Y,REE)2(CO3)9(SO3F)Cl, is a new mineral from Mont Saint-Hilaire, Quebec.  It occurs as blocky, yellow to orange-brown grains up to 2 mm.  Associated minerals include trona, shortite, petersenite-(Ce), catapleiite, minor analcime, and manganotychite.  The mineral has a vitreous luster and white streak.  It is soft (Mohs hardness 3-3.5) and brittle with a conchoidal fracture and perfect {001} cleavage.  Reederite-(Y) is uniaxial negative, w 1.548(1) and e 1.537(1).
It is hexagonal, space group P6, a = 8.773(1), c = 10.746(2) Å, and Z = 1.  The strongest X-ray powder diffraction lines are [d (Å), I, (hkl)]: ;

2.532, 100, (212)
4.39, 80 (102)
2.774, 80, (113)
2.240, 80, (213)

6.20, 40, (101)
1.657, 40 (116,314,322,410)
2.067, 30, (105,303)


     The infrared spectrum is given.  An electron microprobe analysis gave:

Na2O - 34.04
CaO - 0.70
MnO - 1.23

Al2O3 - 1.31
Y2O3 - 10.24
La2O3 - 1.39

Ce2O3 - 3.52
Nd2O3 - 1.99
Er2O3 - 1.19

Dy2O3 - 1.39
SO3 - 5.07
CO2 - 31.91 (calc)

F - 1.86
Cl - 2.05

-O = F + Cl - 1.24


    (plus minor amounts of Fe, Pr, Sm, Gd, and Yb oxides), total 99.14 wt%.
Dmeas = 2.91, Dcalc = 2.85.  The structure has been refined to R = 3.2%.  The carbonate layers are thick slabs accommodating (CO3)2- groups oriented perpendicular to the {001} layering, the large cation polyhedra, and the Cl- and (SO3F)- anions.  The Na atoms adopt a variety of distinct coordinations.  This is the first reported natural occurrence of a fluorosulfate anion.

© 1995  The Mineralogical Society of America