Phosphorus Oligomerization in Zintl Phases: Synthesis,Crystal Structure,and Bonding Analysis of Mixed Alkali and Alkaline‐Earth Metal Phosphides

Pnictides α‐Ba₅P₄ and KBa₄P₅ were prepared by melting the elements. The α‐Ba₅P₄ compound crystallizes in the orthorhombic system (Sm₅Ge₄‐type), space group Pnma, Z = 4, a = 8.330(3), b = 16.503(3), c = 8.405(2)Å, it contains two anionic species : P₂^4— dumbbells and P^3—. The KBa₄P₅ compound crystallizes in the tetragonal system, space group P4₃2₁2, Z = 4, a = 8.559(1), c = 16.102(2)Å, it contains trimers P₃^5— and dumbbells P₂^4—. The crystal structures were solved from single crystal X‐ray data and refined by full‐matrix least‐squares to agreement factors R1 = 0.047 and 0.038, respectively. Using ionic charges, α‐Ba₅P₄ is formulated as [5Ba²⁺, 2P^3—, P₂^4—] and KBa₄P₅ as [K⁺, 4Ba²⁺, P₂^4—, P₃^5—]. The level of oligomerisation in these structures depends upon the overall valence electron content, bonding within the anionic oligomers has been analyzed on the basis of EHMO calculations and compared to classical or hypervalent bonding in other phosphide compounds.     

Synthesis,Crystal Structure,Bonding, and Properties of (Ba6O)(OsN3)2

The new barium nitridoosmate oxide (Ba₆O)(OsN₃)₂ was prepared by reacting elemental barium and osmium (3:1) in nitrogen at 815–830 °C. The crystal structure of (Ba₆O)(OsN₃)₂ as determined by laboratory powder X‐ray diffraction ( , No 148: a=b=8.112(1) Å, c=17.390(1) Å, V=991.0(1) ų, Z=3), consists of sheets of trigonal OsN₃ units and trigonal‐antiprismatic Ba₆O groups, and is structurally related to the “313 nitrides” AE₃MN₃ (AE=Ca, Sr, Ba, M=V–Co, Ga). Density functional calculations, using a hybrid functional, likewise indicate the existence of oxygen in the Ba₆ polyhedra. The oxidation state 4+ of osmium is confirmed, both by the calculations and by XPS measurements. The bonding properties of the OsN₃^5? units are analyzed and compared to the Raman spectrum. The compound is paramagnetic from room temperature down to T=10 K. Between room temperature and 100 K it obeys the Curie–Weiss law (μ=1.68 μ_B). (Ba₆O)(OsN₃)₂ is semiconducting with a good electronic conductivity at room temperature (8.74×10^?2 Ω^?1 cm^?1). Below 142 K the temperature dependence of the conductivity resembles that of a variable‐range hopping mechanism.     

The Metallic Zintl Phase Ba3Si4 – Synthesis,Crystal Structure,Chemical Bonding,and Physical Properties

The Zintl phase Ba₃Si₄ has been synthesized from the elements at 1273 K as a single phase. No homogeneity range has been found. The compound decomposes peritectically at 1307(5) K to BaSi₂ and melt. The butterfly‐shaped Si₄⁶⁻ Zintl anion in the crystal structure of Ba₃Si₄ (Pearson symbol tP28, space group P4₂/mnm, a = 8.5233(3) Å, c = 11.8322(6) Å) shows only slightly different Si‐Si bond lengths of d(Si–Si) = 2.4183(6) Å (1×) and 2.4254(3) Å (4×). The compound is diamagnetic with χ ≈ −50 × 10⁻⁶ cm³ mol⁻¹. DC resistivity measurements show a high electrical resistivity (ρ(300 K) ≈ 1.2 × 10⁻³ Ω m) with positive temperature gradient dρ/dT. The temperature dependence of the isotropic signal shift and the spin‐lattice relaxation times in ²⁹Si NMR spectroscopy confirms the metallic behavior. The experimental results are in accordance with the calculated electronic band structure, which indicates a metal with a low density of states at the Fermi level. The electron localization function (ELF) is used for analysis of chemical bonding. The reaction of solid Ba₃Si₄ with gaseous HCl leads to the oxidation of the Si₄⁶⁻ Zintl anion and yields nanoporous silicon.     

Crystal Structure Determination of Tetrabarium‐digalliumoxide,Ba4Ga2O7

Single crystals of a new barium oxogallate were obtained by growth from a melt at 1500 °C. The compound is monoclinic, with cell parameters a = 17.7447(10) Å, b = 10.6719(5) Å, c = 7.2828(5) Å, β = 98.962(7)°, V = 1362.3(2) ų. The diffraction pattern shows systematic absences corresponding to the space group P12₁/c1. The structure was solved by direct methods followed by Fourier syntheses, and refined using a single crystal diffraction data set (R1 = 0.032 for 2173 reflections with I > 2σ(I)). The chemical composition derived from structure solution is Ba₄Ga₂O₇, with a unit cell content of Z = 6. Main building units of the structure are GaO₄ tetrahedra sharing one oxygen atom to form Ga₂O₇ groups. The Ga–O–Ga bridging angle of one of the two symmetrically independent groups is linear by symmetry. The dimers are crosslinked by barium cations coordinated by six to eight oxygen ligands.     

(Ba6O)(ReN3)2: Synthesis,Crystal Structure and Physical Properties

The reaction of a mixture of barium and rhenium (3:1) at 850 °C under flowing nitrogen yielded the nitride‐oxide (Ba₆O)(ReN₃)₂ (R (No. 148); a = 8.1178(2) Å, c = 17.5651(4) Å; V = 1002.43(5) Å³; Z = 6). According to a structure refinement on X‐ray powder diffraction data, this compound is isostructural to a recently described nitride‐oxide of osmium of analogous composition. The structure consists of sheets of trigonal ReN₃ units and trigonal antiprismatic Ba₆O groups. The Ba–O distance of 2.73 Å is close to the sum of the respective ionic radii. The trigonal ReN₃^5– nitride anion displays a Re–N bond length of 1.94 Å, and is planar within the limits of experimental error. The constitution of the anion was confirmed by IR and Raman spectroscopy. The nitride‐oxide is stable up to 1000 °C, semiconducting (σ = 4.57 × 10^–3 Ω^–1 · cm^–1 at RT), and paramagnetic down to 25 K. A Curie–Weiss analysis resulted in a magnetic moment of μ = 0.68 μ_B per rhenium atom.     

Ba5Cl4(H2O)8(VPO5)8: a novel three‐dimensional framework solid

The novel hydrothermally synthesized title compound, pentabarium tetrachloride octahydrate octakis(oxovanadium phosphate), Ba₅Cl₄(H₂O)₈(VPO₅)₈, crystallizes in the orthorhombic space group Cmca with a unit cell containing four formula units. Two Ba²⁺ cations, two Cl⁻ anions and the O atoms of four water molecules are situated on the (100) mirror plane, while the third independent Ba²⁺ cation is on the intersection of the (100) plane and the twofold axis parallel to a. Two phosphate P atoms are on twofold axes, while the remaining independent P atom and both V atoms are in general positions. The structure is characterized by two kinds of layers, namely anionic oxovanadium phosphate (VPO₅), composed of corner‐sharing VO₅ square pyramids and PO₄ tetrahedra, and cationic barium chloride hydrate clusters, Ba₅Cl₄(H₂O)₈, composed of three Ba²⁺ cations linked by bridging chloride anions. The layers are connected by Ba—O bonds to generate a three‐dimensional structure.     

Ba1.63La7.39Si11N23Cl0.42:Ce3+ – A Nitridosilicate Chloride with a Zeolite‐Like Structure

The nitridosilicate chloride Ba_1.63La_7.39Si₁₁N₂₃Cl_0.42:Ce³⁺ was synthesized by metathesis reaction starting from LaCl₃, BaH₂, CeF₃ and the product of the ammonolysis of Si₂Cl₆. The title compound is stable towards air and moisture. Diffraction data of a microcrystal were recorded using microfocused synchrotron radiation. X‐ray spectroscopy confirms the chemical composition of the crystal. IR spectra corroborate absence of N–H bonds. The compound is homeotypic to Ba₂Nd₇Si₁₁N₂₃ and crystallizes in space group Cmmm with a = 11.009(3), b = 23.243(8), c = 9.706(4) Å and Z = 4, R₁(all) = 0.0174. According to bond valence sum calculations, some crystallographic positions show complete occupancy by Ba or La whereas others contain significant amounts of both elements. In contrast to the structure prototype Ba₂Nd₇Si₁₁N₂₃, Ba_1.63La_7.39Si₁₁N₂₃Cl_0.42:Ce³⁺ contains chloride ions in channels of the SiN₄ tetrahedra network, hinting at various substitution possibilities of the complex zeolite‐like structure.     

Synthesis and Crystal Structure of a New Mixed Orthovanadate-Pyrovanadate Series: MBa2V3O11 or MBa2V2PO11 with M = Bi, In, or a Rare Earth

A new series of vanadates with the general formula M Ba₂V₃O₁₁, where M may be Bi, In, or a rare earth, has been synthesized and structurally characterized by single crystal X-ray diffraction and powder X-ray diffraction. The general formula may be rewritten as M Ba₂(VO₄)(V₂O₇) to emphasize that there is one orthovanadate group and one pyrovanadate group in each formula unit. Up to one-third of the vanadium may be replaced by phosphorous, leading to the general formula M Ba₂V₂PO₁₁. However, phosphorous shows no preference between the ortho and pyro groups. Both M Ba₂V₃O₁₁ and M Ba₂V₂PO₁₁ crystallize in the monoclinic system with the space group P2₁/_c and Z = 4. The cell parameters from single crystal X-ray data of BiBa₂V₃O₁₁ are a = 12.332(4) Å, b = 7.750(4) Å, c = 11.279(4) Å, β = 103.22(3)°, V = 1049(1) ų; and for BiBa₂PO₁₁ are a = 12.266(2) Å, b = 7.615(2) Å, c = 11.312(2) Å, β = 103.32(2)°, V = 1028.2(2) ų. The Bi atom coordinates to six oxygen atoms forming a distorted octahedron, and the edge sharing of BiO₆ octahedra results in a BiO₄ chain along the b axis. There are two types of Ba atoms with coordination numbers of 10 and 11. There are three types of tetrahedral (T) atoms in these structures. The nonequivalent T atoms of the pyro group give T-O-T angles of 167 and 171° in BiBa₂V₃O₁₁ and BiBa₂V₂PO₁₁, respectively. Isostructural M Ba₂V₃O₁₁ compounds were prepared in which M is In, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, or Lu.     

Das Indid‐Hydrid Ba9[In]4[H]: Synthese,Kristallstruktur, NMR‐Spektroskopie,Chemische Bindung

The new indide hydride Ba₉[In]₄[H] was synthesized from the elements in stoichiometric proportions using the inherent hydrogen content of commercial elemental barium as hydrogen source. Its structure, constituting a new type, was determined using single‐crystal X‐ray data (tetragonal, space group I4/m, a = 1397.3(2), c = 591.8(1) pm, Z = 2) in sufficient quality (R1 = 0.0261) to allow identification and location of the hydride ion as well as the refinement of its thermal parameter. The crystal structure of Ba₉[In]₄[H] exhibits isolated indium atoms, which are coordinated by 10 barium cations in a cubicosahedral arrangement. The hydride anions are octahedrally surrounded by six Ba²⁺ cations. According to [HBa₄Ba_2/2] these octahedra are connected by opposite corners to form chains running along the c axis. The presence of the hydride ion was determined by solid state NMR spectroscopy, where the chemical shift of the ¹H‐MAS‐NMR signal of–9.0 ppm nicely corresponds to the values in BaH₂ and other metallid hydrides. Like in other binary alkaline‐earth indides, the band structure calculated in the frame of the FP‐LAPW methods shows a pseudo band gap slightly above the Fermi level, associated with the electron precise valence electron count after Zintl (isolated In^5–). The title compound was compared to other hydrides and indides both according to the structural as well as the bonding features.     

Ba2In2Q5 (Q = S,Se): Synthesis,Crystal Structures,Electronic Structures,and Optical Properties

Two ternary metal chalcogenides, Ba₂In₂Q₅ (Q = S, Se) were successfully synthesized by solid‐state reactions. They are isostructural and crystallize in the orthorhombic space group Pbca (no. 61). Both of them have a similar three‐dimensional (3D) framework structure, which is composed of [InQ₄] (Q = S, Se) tetrahedra that are alternatingly connected on layer in the ab plane, with Ba²⁺ cations arranged between In–S or In–Se layers for electric charge balance. The measured Raman and IR spectra show that title compounds have broad transparency range up to 20 μm. From the UV/Vis/NIR diffuse reflectance spectra, it can be seen that the bandgaps of Ba₂In₂S₅ and Ba₂In₂S₅ are 2.47 eV and 2.12 eV, which are larger than these of the calculation values (Ba₂In₂S₅, 2.362 eV and Ba₂In₂Se₅, 1.908 eV), respectively. The calculated partial densities of states indicate that the bandgaps are determined by the interaction of S‐3p and In‐5s (Ba₂In₂S₅) or Se‐4p and In‐5s (Ba₂In₂Se₅), respectively. The calculated birefringences (Δn) are about 0.03 (Ba₂In₂S₅) and 0.05 (Ba₂In₂Se₅) as the wavelength above 1 μm, respectively.     

Zur Chemie und Strukturchemie von Phosphiden und Polyphosphiden. 581) Tetrabariumtriphosphid,Ba4P3: Darstellung und Kristallstruktur

Chemistry and Structural Chemistry of Phosphides and Polyphosphides. 58. Tetrabariumtriphosphide, Ba₄P₃: Preparation and Crystal Structure Ba₄P₃ is obtained from the elements in the molar ratio 4:3 or by reaction of Ba₃P₂ and Ba₅P₄ in the molar ratio 1:1 (steel ampoules with inner corundum crucibles; 1 490 K). The greyish black, easily hydrolysing compound crystallizes in a new structure type oP56. The structure shows two crystallographically independent dumbbells P₂^4? (d(P? P) = 225 and 232 pm) and isolated ions P^3? corresponding to (Ba²⁺)₈(P₂^4?)₄(P^3?)₄. The partial structure of the Ba atoms forms a complex network of trigonal prisms with tetrahedral and square pyramidal holes, as well as polyhedra with 14 faces (CN 10) which are icosahedron derivatives. The P^3? anions center trigonal prisms and the 14 face polyhedron. The P-atoms of the P₂^4? dumbbells center neighboring trigonal prisms with common square faces. (Pbam (no. 55); a = 1 325.4(2) pm, b = 1 256.2(2) pm, c = 1 127.3 pm; Z = 8).     

Quaternary Sulfide Ba6Zn6ZrS14: Synthesis,Crystal Structure,Band Structure,and Multiband Physical Properties

Ba₆Zn₆ZrS₁₄ was synthesized by a traditional salt‐melt method with KI as flux. The pale yellow crystals of Ba₆Zn₆ZrS₁₄ crystallize in the tetragonal space group I4/mcm with a=16.3481 (4) Å and c=9.7221(6) Å. The structure features unique one‐dimensional parallel [Zn₆S₉]^6? and [ZrS₅]^6? straight chains. The D_2h‐symmetric [Zn₆S₉]^6? cluster serves as the building block of the [Zn₆S₉]^6? chains. A powder sample was investigated by X‐ray diffraction, optical absorption, and photoluminescence measurements. The compound shows multiple‐absorption character with three optical absorption edges around 1.78, 2.50, and 2.65 eV, respectively, which are perfectly consistent with the results of first‐principles calculations. Analysis of the density of states further revealed that the three optical absorption bands are attributable to the three S(3p⁶)→Zr(4d⁰) transitions due to the splitting of the Zr 4d orbitals in the D_4h crystal field. The multiband nature of Ba₆Zn₆ZrS₁₄ also results in photocatalytic activity under visible‐light irradiation and three band‐edge emissions.     

Synthesis,Structure Analysis,and Antitumor Activity of （R）-2,4-Dioxo-5-fluoro-l-[1-（methoxycarbonyl） Ethylaminocarbonylmethyl]-1,2,3,4-tetrahydropyrimidine

A new dipeptide compound, （R）-2,4-dioxo-5-fluoro-1-[1-（methoxycarbonyl） ethylaminocarbonylmethyl]-1,2,3, 4-tetrahydropyrimidine （5-FUAPM）, has been synthesized and identified by means of elemental analysis, IR, ^1H NMR and ^13C NMR spectra. The single crystal of compound 5-FUAPMoDMF was also obtained and characterized by DSC-TGA techniques. The crystal belongs to orthorhombic space group P212121 with the cell parameters： a= 0.4740（7） nm, b= 1.923（3） nm, c= 1.9229 nm, a=β=y=90°, V= 1.753 nm^3, Z=4, Dc= 1.312 g/cm^3, Mr=346.32, F（000）=728 and u=0.111 mm^-1. The final R and wR are 0.1378 and 0.2862, respectively. The result of the biological test showed that the compound 5-FUAPM has certain antitumor activities.     

Crystal Structure, (31P, 13C) MAS-NMR,IR Spectroscopy and Thermal Investigations of 2,6-Dimethylanilinium Dihydrogenmonophosphate Monohydrate

Chemical preparation, crystal structure, thermal analysis, IR absorption, and NMR studies are given for a new hybrid organic-inorganic compound, the (2,6-dimethyanilinium) dihydrogenophosphate monohydrate [C ₈ H ₁₂ N]H ₂ PO ₄ ·H ₂ O. This compound crystallizes in a triclinic P=1 unit-cell, with a = 7.392(5) Å, b = 8.323(3) Å, c = 10.306(5) Å, α = 95.769 (4)°, β = 102.642 (3)°, γ = 113.498(2)°, V = 554.88(5) Å ³ , and Z = 2. Its crystal structure is determined and refined to R = 0.040 with 1942 independent reflections. The atomic arrangement can be described by inorganic layers built by H ₂ PO ₄ ^? anions, and H ₂ O molecules with which the organic molecules perform different interactions to form a stable 3D network. Solid state ³¹ P and ¹³ C CP-MAS-NMR spectroscopies are in agreement with the X-ray structure.     

Die neuen Schichtsilicate Ba3Si6O9N4 und Eu3Si6O9N4

The New Layer‐Silicates Ba₃Si₆O₉N₄ and Eu₃Si₆O₉N₄ The new oxonitridosilicate Ba₃Si₆O₉N₄ has been synthesized in a radiofrequency furnace starting from BaCO₃, amorphous SiO₂ and Si₃N₄. The reaction temperature was at about 1370 °C. The structure of the colorless compound has been determined by single‐crystal X‐ray diffraction analysis (Ba₃Si₆O₉N₄, space group P3 (no. 143), a = 724.9(1) pm, c = 678.4(2) pm, V = 308.69(9)· 10⁶ pm³, Z = 1, R1 = 0.0309, 1312 independent reflections, 68 refined parameters). The compound is built up of corner sharing SiO₂N₂ tetrahedra forming corrugated layers between which the Ba²⁺ ions are located. Substitution of barium by europium leads to the isotypic compound Eu₃Si₆O₉N₄. Because no single‐crystals could be obtained, a Rietveld refinement of the powder diffractogram was conducted for the structure refinement (Eu₃Si₆O₉N₄, space group P3 (no. 143), a = 711.49(1) pm, c = 656.64(2) pm, V = 287.866(8) ·10⁶ pm³, R_p = 0.0379, R_F² = 0.0638). The ²⁹Si MAS‐NMR spectrum of Ba₃Si₆O₉N₄ shows two resonances at ?64.1 and ?66.0 ppm confirming two different crystallographic Si sites.     

Synthesis,Crystal Structure and Vibrational Spectra of Barium Cyclotetraphosphate Hydrate Ba2(P4O12)∙3.5H2O

Barium tetrametaphosphate hydrate Ba₂(P₄O₁₂)∙3.5H₂O was synthesized as a single‐phase crystalline powder starting from an aqueous solution of barium hydroxide and phosphorus pentoxide at 300 K. Ba₂(P₄O₁₂)∙3.5H₂O crystallizes in a new structure type in which the Ba²⁺ ions form a distorted hexagonal diamond‐like arrangement with the (P₄O₁₂)^4– anions in the trigonal prismatic voids (Ba₂(P₄O₁₂)∙3.5H₂O, C2/c, Z = 4, a = 777.3(2), b = 1297.6(2), c = 1346.1(3) pm, b = 95.38(2)°, wR₂ = 0.071, R₁ = 0.018, 1180 reflections, 118 parameters). The vibrational spectra of Ba₂(P₄O₁₂)∙3.5H₂O and its thermal behavior up to 720 K are also reported.     

Two New Tetranuclear Cluster-based Coordination Polymers based on Isomorphic Semi-rigid Tetracarboxylate Ligands: Syntheses,Structures, and Luminescent Properties

Two new tetranuclear cluster-based compounds, namely [Cd₂(L1)(H₂O)(DMA)]_n ( 1 ) and [Cd₂Ba₂(L2)(H₂O)₆(DMA)]_n ( 2 ) [H₄L1 = 3-(3',5'-dicarboxylphenoxy) phthalic acid, H₄L2 = 6-(3',4'-dicarboxyl-phenoxy) isophthalic acid, DMA = N,N'-dimethylacetamide], were successfully synthesized under solvothermal conditions and structurally characterized by single-crystal X-ray diffraction analyses. Compound 1 features a two-dimensional (2D) layered framework with tetranuclear [Cd₄(COO)₆] clusters as building subunits, and can be simplified into a binodal (3, 6)-connected kgd topological network with the schläfli symbol of {4³}₂{4⁶;6⁶;8³}, and compound 2 features a three-dimensional (3D) complicated framework based on heterometallic tetranulear [Cd₂Ba₂(COO)₈] cluster subunits, and can be simplified into a binodal (3, 6)-connected topological network. In addition, compounds 1 and 2 not only have high thermal stabilities but also show strong luminescent emissions at room temperature.     

LixNayBa14LiN6: New Representatives of the Subnitride Family

Three new metal‐rich phases, Li₄Na₁₁Ba₁₄LiN₆, Li₅Na₁₀Ba₁₄LiN₆ and Na₁₄Ba₁₄LiN₆ have been prepared and their crystal structure determined. According to single crystal and powder X‐ray diffraction data, all compounds crystallize with cubic unit cells (Li₄Na₁₁Ba₁₄LiN₆: , a = 17.874(2) Å, Z = 4, V = 5710(1) ų; Li₅Na₁₀Ba₁₄LiN₆: , a = 17.799(1) Å, Z = 4, V = 5638.7(6) ų; Na₁₄Ba₁₄LiN₆: , a = 17.7955(5) Å, Z = 4, V = 5635.6(2) Å). The last mentioned compound crystallizes in the Na₁₄Ba₁₄CaN₆ type, and both Li₄Na₁₁Ba₁₄LiN₆ and Li₅Na₁₀Ba₁₄LiN₆ have related structures. These compounds open a series of metal‐rich Ba nitrides, containing the new Ba₁₄LiN₆ cluster.     

The Crystal Structures of SrAlF5 and Ba0.43(1)Sr0.57(1)AlF5

Two members belonging to the pseudobinary phase diagram of Ba/SrF₂ and AlF₃ were synthesized. Single domain crystals of SrAlF₅ and Ba_0.43(1)Sr_0.57(1)AlF₅ were prepared from the corresponding metal fluorides. The mixed compound Ba_0.43(1)Sr_0.57(1)AlF₅ has been synthesized and characterized in detail for the first time. The structure of SrAlF₅ was reinvestigated; a superstructure was found which is absent in Ba_0.43(1)Sr_0.57(1)AlF₅. The compounds crystallize at room temperature in the centrosymmetric tetragonal space groups I4₁/a and I4/m. Lattice parameters are a = b= 1988.22(14), c = 1432.24(19) and a = b = 1431.32(14), c = 722.83(7) pm. Both structures differ mainly in the AlF₆ arrangement situated in the cavities of the matrix structure. In SrAlF₅, ordered dimer [Al₂F₁₀]^4– units are found, whereas in the Ba²⁺ mixed sample a linear chain of AlF₆ octahedra is observed. For both compounds no partial occupation was observed. Sm²⁺ doped samples are further characterized by luminescence measurements. Four independent sites of alkaline earth atoms were found in the Sm²⁺ luminescence of the host SrAlF₅.     

Synthesis,Persistent Luminescence,and Thermoluminescence Properties of Yellow Sr3SiO5:Eu2+,RE3+ (RE=Ce,Nd, Dy,Ho, Er,Tm, Yb) and Orange‐Red Sr3−xBaxSiO5:Eu2+, Dy3+ Phosphor

Sunlight‐excitable orange or red persistent oxide phosphors with excellent performance are still in great need. Herein, an intense orange‐red Sr_3?xBa_xSiO₅:Eu²⁺,Dy³⁺ persistent luminescence phosphor was successfully developed by a two‐step design strategy. The XRD patterns, photoluminescence excitation and emission spectra, and the thermoluminescence spectra were investigated in detail. By adding non‐equivalent trivalent rare earth co‐dopants to introduce foreign trapping centers, the persistent luminescence performance of Eu²⁺ in Sr₃SiO₅ was significantly modified. The yellow persistent emission intensity of Eu²⁺ was greatly enhanced by a factor of 4.5 in Sr₃SiO₅:Eu²⁺,Nd³⁺ compared with the previously reported Sr₃SiO₅:Eu²⁺, Dy³⁺. Furthermore, Sr ions were replaced with equivalent Ba to give Sr_3?xBa_xSiO₅:Eu²⁺,Dy³⁺ phosphor, which shows yellow‐to‐orange‐red tunable persistent emissions from λ=570 to 591 nm as x is increased from 0 to 0.6. Additionally, the persistent emission intensity of Eu²⁺ is significantly improved by a factor of 2.7 in Sr_3?xBa_xSiO₅:Eu²⁺,Dy³⁺ (x=0.2) compared with Sr₃SiO₅:Eu²⁺,Dy³⁺. A possible mechanism for enhanced and tunable persistent luminescence behavior of Eu²⁺ in Sr_3?xBa_xSiO₅:Eu²⁺,RE³⁺ (RE=rare earth) is also proposed and discussed.