Intracrystalline distribution of ferrous and ferric iron within pumpellyites (VIIW8VIX4VIY8IVZ12O56–n(OH)n, Z = 1) from low-grade metamorphic green rocks of the Kanogawa unit in the Northern Chichibu Belt, Hijikawa district, western Shikoku, Japan, was investigated using electron microprobe analysis, X-ray Rietveld refinement, and 57Fe Mössbauer spectroscopic analysis to verify the regularity of the distribution of Fe within the octahedral X and Y sites in pumpellyite and its effect on the pumpellyite structure. Two Fe-rich pumpellyite samples, labelled CLW and CHG, with average total Fe2O3 of 10.01±1.69 and 16.07±1.08 wt.%, respectively, were separated from the rock samples. The site occupancies at the X and Y sites in the CLW and CHG pumpellyites, refined using powder X-ray diffraction data, are X[Mg0.298Fe0.298(5)Al0.405]Y[Fe0.191Al0.809] and X[Mg0.244Fe0.42(1)Al0.34]Y[Fe0.32Al0.68], respectively. The Fe2+:Fe3+ ratio of the CLW pumpellyite, determined using Mössbauer spectroscopy, is 12(1):88(3). By combining the average chemical composition data, the site occupancies at the X and Y sites, and the Fe2+:Fe3+ ratio of the CLW pumpellyite, the chemical formulae of CLW and CHG pumpellyites are constructed as (Ca7.96K0.02Na0.01)Σ7.99(Mg1.19Mn2+0.09Fe2+0.39Fe3+0.71Al1.62)Σ4.00(Al6.47Fe3+1.50V0.02Ti0.01)Σ8.00Si12.26O43.33(OH)12.67 and (Ca8.01K0.01)Σ8.02(Mg0.97Mn2+0.02Fe2+0.63Fe3+1.03Al1.19)Σ4.01(Al5.44Fe3+2.55V0.01)Σ8.00Si12.02O42.69OH)13.31, respectively, implying that the proper name of both pumpellyites is pumpellyite-(Al). The intracrystalline distribution coefficients of Fe3+ versus Al between the X and Y sites, KD = (Fe3+/Al)X/(Fe3+/Al)Y, are 1.62 and 1.90 for the CLW and CHG pumpellyites, respectively, implying stronger X-site preference of Fe3+ than Al3+. In the CHG pumpellyite, where the Fe contents at the X and Y sites are higher than in the CLW pumpellyite, the mean <X–O> and <Y–O> distances are 2.06 and 1.98 Å, respectively, which are larger than <X–O> = 2.040 and <Y–O> = 1.944 Å in the CLW pumpellyite. The unit-cell parameters of the CHG pumpellyite are a = 8.8672(3), b = 5.9562(2), c = 19.1899(6) Å, β = 97.473(2)° with V = 1004.9(2) Å3 and are larger than those of the CLW pumpellyite, a = 8.8456(4), b = 5.9393(2), c = 19.1613(8) Å, β = 97.461(3)° with V = 998.14(7) Å3.

秩父北部鹿川单元低品位变质绿色岩石中二价铁和三价铁在泵氏铁矿 ( VII W 8 VI X 4 VI Y 8 IV Z 12 O 56– n (OH) n , Z = 1) 中的晶内分布利用电子探针分析、X射线Rietveld精修和57 Fe穆斯堡尔光谱分析对日本四国西部比地川地区的Belt进行了研究，验证了泵辉石中Fe在八面体X和Y位点内的分布规律及其影响关于泵贝氏体结构。从岩石样品中分离出两个富铁泵贝石样品，标记为CLW 和CHG，平均总Fe 2 O 3分别为10.01±1.69 和16.07±1.08 wt.%。 CLW 和 CHG 泵贝利岩中X和Y位点的位点占用情况，使用粉末 X 射线衍射数据精修为X [Mg 0.298 Fe 0.298(5) Al 0.405 ] Y [Fe 0.191 Al 0.809 ] 和X [Mg 0.244分别为Fe 0.42(1) Al 0.34 ] Y [Fe 0.32 Al 0.68 ]。使用穆斯堡尔谱测定，CLW 泵贝氏石的Fe 2+ : Fe 3+比率为 12(1):88(3)。结合CLW泵贝氏石的平均化学成分数据、X位点和Y位点的位点占有率以及Fe 2+ :Fe 3+比，构建CLW和CHG泵贝氏石的化学式为(Ca 7.96 K 0.02 Na 0.01 ) Σ7.99 (Mg 1.19 Mn 2+ 0.09 Fe 2+ 0.39 Fe 3+ 0.71 Al 1.62 ) Σ4.00 (Al 6.47 Fe 3+ 1.50 V 0.02 Ti 0.01 ) Σ8.00 Si 12.26 O 43.33 (OH) 12.67和(Ca 8.01 K 0.01 ) Σ8.02 (Mg 0.97 Mn 2+0.02 Fe 2+ 0.63 Fe 3+ 1.03 Al 1.19 ) Σ4.01 (Al 5.44 Fe 3+ 2.55 V 0.01 ) Σ8.00 Si 12.02 O 42.69 OH) 13.31，这意味着这两种泵佩尔石的正确名称是泵佩尔石-(艾尔）。CLW 和 CHG 泵贝氏石的 Fe 3+与 Al 在X和Y位点之间的晶内分配系数K D = (Fe 3+ /Al) X /(Fe 3+ /Al) Y分别为 1.62 和 1.90 ，这意味着Fe 3+的X位优先性强于 Al 3+。在 CHG 泵贝利石中， X和Y位点的 Fe 含量高于 CLW 泵贝利石，平均 < X –O> 和 < Y –O> 距离分别为 2.06 和 1.98 Å，大于 < CLW 泵锰矿中的X –O> = 2.040 和 < Y –O> = 1.944 Å。 CHG 泵贝利石的晶胞参数为a = 8.8672(3)、b = 5.9562(2)、c = 19.1899(6) Å、β = 97.473(2)°，其中V = 1004.9(2) Å 3为比CLW泵贝利石大，a = 8.8456(4)，b = 5.9393(2)，c = 19.1613(8) Å，β = 97.461(3)°，V = 998.14(7) Å 3。