Question

plass-10rep, ads_fes pre.t
00-024-0076
00-001-1053
position °2θ (copper (cu))

Explanation:

🆕 New Concept Discovered: XRD Phase Identification
Matching experimental diffraction peaks to reference patterns.

Step 1: Analyze the Experimental Pattern

The top red curve represents the experimental X-ray diffraction (XRD) pattern labeled "Plass-10rep, ADS_FeS pre.T".

• This pattern shows a high background with relatively broad, low-intensity peaks, indicating a material with low crystallinity or small crystallite size (often characteristic of amorphous or poorly crystalline iron sulfide phases).
• Key experimental peaks are visible at approximately:
• \( 2\theta \approx 33^\circ \) (a distinct, sharp peak)
• \( 2\theta \approx 43^\circ \) (a broad, weak feature)
• \( 2\theta \approx 53^\circ - 56^\circ \) (a broad peak region)

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Step 2: Compare with Reference Pattern 1 (00-024-0076)

The middle green curve represents the reference pattern 00-024-0076 (typically corresponding to Troilite or Pyrrhotite-type iron sulfide, \( \text{Fe}_{1-x}\text{S} \) or \( \text{FeS} \)).

• It features prominent, sharp diffraction peaks at:
• \( 2\theta \approx 30^\circ \)
• \( 2\theta \approx 33.2^\circ \)
• \( 2\theta \approx 37^\circ \)
• \( 2\theta \approx 43.5^\circ \)
• \( 2\theta \approx 53^\circ \)
• \( 2\theta \approx 56^\circ \)
• Comparing this to the experimental red pattern:
• The sharp experimental peak at \( 2\theta \approx 33^\circ \) matches the strongest reference peak of this phase at \( 33.2^\circ \).
• The broad features around \( 43^\circ \) and \( 53^\circ - 56^\circ \) in the experimental data align well with the positions of the major peak clusters in this reference pattern.

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Step 3: Compare with Reference Pattern 2 (00-001-1053)

The bottom grey curve represents the reference pattern 00-001-1053 (typically corresponding to Halite/NaCl or another cubic phase used as an internal standard or representing a different phase).

• It features prominent peaks at:
• \( 2\theta \approx 27.3^\circ \)
• \( 2\theta \approx 31.6^\circ \)
• \( 2\theta \approx 45.4^\circ \)
• \( 2\theta \approx 56.4^\circ \)
• \( 2\theta \approx 66.2^\circ \)
• Comparing this to the experimental red pattern:
• The experimental pattern does not show the characteristic strong peak at \( 2\theta \approx 31.6^\circ \) or \( 45.4^\circ \).
• Therefore, this phase is either absent or below the detection limit in the experimental sample.

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Answer:

The experimental sample "Plass-10rep, ADS_FeS pre.T" is a match for the reference pattern 00-024-0076 (Iron Sulfide, \( \text{FeS} \)).

The primary matching peak is located at \( 2\theta \approx 33.14^\circ \) (as indicated in the status bar at the bottom: Pos. [°2θ]: 33.1424), which aligns perfectly with the main peak of the green reference pattern. The other reference pattern (00-001-1053) does not show a good match with the experimental peak positions.