TY - JOUR

T1 - The crystal structure of epifanovite

AU - Panikorovskii, T. L.

AU - Krivovichev, S. V.

AU - Yakovenchuk, V. N.

AU - Ivanyuk, G. Yu

PY - 2017/1/1

Y1 - 2017/1/1

N2 - The crystal structure of epifanovite, NaCaCu 5 (PO 4 ) 4 [AsO 2 (OH) 2 ] 7H 2 O, a new mineral from the oxidation zone of the Kester tin deposit, was determined by direct methods and refined to R 1 = 0.087 on the basis of 2147 independent observed reflections. The mineral is monoclinic, P2 1 /m, a = 9.6911(8), b = 9.7547(9), c = 9.9632(14) A, β = 102.237(10)°, V = 920.46(17) A 3 , Z = 2. The crystal structure of epifanovite contains four symmetrically independent Cu sites, each coordinated by five O atoms by forming short equatorial (1.905-1.964 A) and one elongated (2.467-2.720 A) Cu-O bonds. Four CuO 5 pyramids centered by the Cu2, Cu3 and Cu4 sites are linked at the O11 atom to form [Cu 4 O 13 ] tetramers. The [Cu 4 O 13 ] tetramers and Cu1O 5 pyramids are linked via phosphate groups into the complex, which is incrustated by disordered [AsO 2 (OH) 2 ] - group to form fundamental building blocks in the structure. The blocks are linked through phosphate groups to form layers parallel to the (001) plane. The layers are joined into a three-dimensional framework by sharing of the apical atoms of the Cu1O5 pyramids and O atoms of disordered arsenate groups. Epifanovite is related to the group of minerals and inorganic compounds based upon the [Cu 4 O(TO 4 ) 4 ] layers (T = As, P). The most closely related to epifanovite are monoclinic polytypes of the andyrobertsite-calcioandyrobertsite KMeCu 5 (AsO 4 ) 4 [As(OH) 2 O 2 ] 2H 2 O (Me = Cd, Ca).

AB - The crystal structure of epifanovite, NaCaCu 5 (PO 4 ) 4 [AsO 2 (OH) 2 ] 7H 2 O, a new mineral from the oxidation zone of the Kester tin deposit, was determined by direct methods and refined to R 1 = 0.087 on the basis of 2147 independent observed reflections. The mineral is monoclinic, P2 1 /m, a = 9.6911(8), b = 9.7547(9), c = 9.9632(14) A, β = 102.237(10)°, V = 920.46(17) A 3 , Z = 2. The crystal structure of epifanovite contains four symmetrically independent Cu sites, each coordinated by five O atoms by forming short equatorial (1.905-1.964 A) and one elongated (2.467-2.720 A) Cu-O bonds. Four CuO 5 pyramids centered by the Cu2, Cu3 and Cu4 sites are linked at the O11 atom to form [Cu 4 O 13 ] tetramers. The [Cu 4 O 13 ] tetramers and Cu1O 5 pyramids are linked via phosphate groups into the complex, which is incrustated by disordered [AsO 2 (OH) 2 ] - group to form fundamental building blocks in the structure. The blocks are linked through phosphate groups to form layers parallel to the (001) plane. The layers are joined into a three-dimensional framework by sharing of the apical atoms of the Cu1O5 pyramids and O atoms of disordered arsenate groups. Epifanovite is related to the group of minerals and inorganic compounds based upon the [Cu 4 O(TO 4 ) 4 ] layers (T = As, P). The most closely related to epifanovite are monoclinic polytypes of the andyrobertsite-calcioandyrobertsite KMeCu 5 (AsO 4 ) 4 [As(OH) 2 O 2 ] 2H 2 O (Me = Cd, Ca).

KW - Copper phosphate-arsenate

KW - Crystal structure

KW - Disorder

KW - Epifanovite

KW - Kester deposit

UR - http://www.scopus.com/inward/record.url?scp=85049902554&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:85049902554

VL - 146

SP - 39

EP - 50

JO - ЗАПИСКИ РОССИЙСКОГО МИНЕРАЛОГИЧЕСКОГО ОБЩЕСТВА

JF - ЗАПИСКИ РОССИЙСКОГО МИНЕРАЛОГИЧЕСКОГО ОБЩЕСТВА

SN - 0869-6055

IS - 3

ER -