Second update on compounds with kröhnkite-type chains
Second update on compounds with kröhnkite-type chains
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具有 kröhnkite 型链的化合物的第二次更新
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
M. Fleck
中科院分区：
文献类型：
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作者：
U. Kolitsch;M. Fleck
本文报道了五种新合成的复盐二水合物的单晶X-射线衍射结构。以下三种硒酸盐（VI）、硫酸盐（VI）和铬酸盐（VI）化合物都含有克氏-[Na 2Cu（SO 4）2 · 2 H2O]-型无限四面体-八面体链：K2Zn（SeO4）2 ·2H2O（a = 5.571（1），B = 6.586（1），c = 7.458（2）π，α = 111.14（3），β = 96.35（3），γ = 106.15（3）°，V = 238.26（8）π 3，R（F）= 0.037，空间群P-1，no.2，Z = 1），K_2Co（SO_4）_2·2H_2O（a = 5.327（1），B = 6.566（1），c = 7.256（2）π，α = 110.74（3），β = 95.00（3），γ = 107.02（3）°，V = 221.72（8）π 3，R（F）= 0.037，空间群P-1，no.2，Z = 1），Rb_2Cd（CrO_4）_2·2H_2O（a = 6.852（1），B = 7.706（2），c = 11.362（2）°，α = 73.07（3），β = 75.11（3），γ = 69.63（3）°，V = 529.88（18）° 3，R（F）= 0.026，空间群P-1，no.2，Z = 2）。其余两种化合物，同型重铬酸盐K2 Co（Cr2 O 7）2 · 2 H2O和Cs2 Cd（Cr2 O 7）2 · 2 H2O的晶体结构（a = 6.801（1）/7.368（1），B = 7.723（1）/8.051（2），c = 7.814（1）/8.047（2）°，α = 89.23（3）/88.68（3），β = 81.05（3）/81.12（3），γ = 64.39（3）/63.81（3）°，V = 364.93（14）/422.66（16）3，R（F）= 0.022/0.025，空间群P-1，no. 2，Z = 1）与克氏石型化合物的结构密切相关;结构中含有Cr2 O 7基团，具有与克氏石型含氧盐中XO 4基团相同的桥接作用。这两种重铬酸盐与它们的K-Zn-和K-Cd-类似物是同型的，尽管Cs_2Cd（Cr_2O_7）_2·2H_2O中的氢键方案完全不同。描述了这五个新化合物的原子排列，并指出了它们的特殊之处。关于我们先前提出的分类，讨论了与其他克陨石型和类矿物和化合物的结构关系（Fleck等人，2002年; Fleck和Kolitsch，2003年）。化合物Rb 2Cd（CrO 4）2 · 2 H2O代表第一个克朗斯特型铷化合物和第一个具有结构类型D的铬酸盐。Cs2 Cd（Cr2 O 7）2 · 2 H2O是已知的第一个含有类铬榴石链的铯化合物。
Abstract The crystal structures of five new synthetic double salt dihydrates have been determined from single-crystal X-ray diffraction data. The following three selenate(VI), sulphate(VI) and chromate(VI) compounds all contain kröhnkite-[Na2Cu(SO4)2 · 2 H2O]-type infinite tetrahedral-octahedral chains: K2Zn(SeO4)2 · 2 H2O (a = 5.571(1), b = 6.586(1), c = 7.458(2) Å, α = 111.14(3), β = 96.35(3), γ = 106.15(3)°, V = 238.26(8) Å3, R(F) = 0.037, space group P-1, no. 2, Z = 1), K2Co(SO4)2 · 2 H2O (a = 5.327(1), b = 6.566(1), c = 7.256(2) Å, α = 110.74(3), β = 95.00(3), γ = 107.02(3)°, V = 221.72(8) Å3, R(F) = 0.037, space group P-1, no. 2, Z = 1), Rb2Cd(CrO4)2 · 2 H2O (a = 6.852(1), b = 7.706(2), c = 11.362(2) Å, α = 73.07(3), β = 75.11(3), γ = 69.63(3)°, V = 529.88(18) Å3, R(F) = 0.026, space group P-1, no. 2, Z = 2). The crystal structures of the two remaining compounds, the isotypic dichromates K2Co(Cr2O7)2 · 2 H2O and Cs2Cd(Cr2O7)2 · 2 H2O (a = 6.801(1)/7.368(1), b = 7.723(1)/8.051(2), c = 7.814(1) /8.047(2) Å, α = 89.23(3)/88.68(3), β = 81.05(3)/81.12(3), γ = 64.39(3)/63.81(3)°, V = 364.93(14)/422.66(16) Å3, R(F) = 0.022/0.025, space group P-1, no. 2, Z = 1) are closely related to those of kröhnkite-type compounds; the structure contains Cr2O7 groups assuming the same bridging role that XO4 groups have in kröhnkite-type oxysalts. Both dichromates are isotypic with their K—Zn- and K—Cd-analogues although the hydrogen bonding scheme in Cs2Cd(Cr2O7)2 · 2 H2O is completely different. The atomic arrangements of the five new compounds are described and unusual features are pointed out. Structural relations with other kröhnkite-type and -like minerals and compounds are discussed with respect to our previously proposed classification (Fleck et al., 2002; Fleck and Kolitsch, 2003). The compound Rb2Cd(CrO4)2 · 2 H2O represents both the first kröhnkite-type rubidium compound and the first chromate with structure type D. Cs2Cd(Cr2O7)2 · 2 H2O is the first caesium compound known to contain kröhnkite-like chains.