Author Topic: documentation of RP5O14 crystals  (Read 404 times)

crystalgrower

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documentation of RP5O14 crystals
« on: April 26, 2023, 07:51:32 AM »
There were three generations of RP5O14 mounts.  I will separate the three to allow all available documents to be posted.

#1. China crystals mounted by Astimex Scientific and sold up to 2010 by SPI Supplies as AS-02758 (see attached China references).  All references identify these as monoclinic and they were only sold mounted.

 The distinguishing feature is that the wells were 1.2mm not 2mm. 

A custom orbital polishing machine was used after mounts were trimmed flat with a diamond saw. Photos of all grains were made starting in 2006, using reflected [polarized light that made all grain boundaries and twin contacts visible.   John Rucklidge had a firm policy to consider all claims of defective materials and these were replaced free of charge until he gave up ownership of the company at the end of 2012.  I never heard of any defect (other than "wrong element")  being reported for this product stream.



« Last Edit: May 03, 2023, 09:32:29 AM by crystalgrower »

crystalgrower

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Re: documentation of RP5O14 crystals
« Reply #1 on: April 26, 2023, 08:07:28 AM »
#2. Crystals grown at Astimex Scientific and sold under both brands from mid-2009 to late 2012.  These orthorhombic crystals were sold both loose and mounted (SPI code AS-02759) and were included in custom mounts.   Mounts had 2mm wells drilled into steel mounts.  Crystals were polished with same equipment as #1.

During this time, sale of monoclinic crystals was suspended.  The policy of replacement of defective materials was in effect but no claims were made before the  end of 2012.

I included two reports about ErP5O14 to illustrate the very common problem encountered in actual crystal growing.

It is also important to read older "crystal structure" reports carefully as they were usually a computed simulation of distortion of the monoclinic structure.  The orthorhombic structure of LaP5O14 was reported in 1969 from Weissenberg camera work but the full direct structure determination had to wait until 2008.
« Last Edit: May 05, 2023, 09:05:05 AM by crystalgrower »

crystalgrower

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Re: documentation of RP5O14 crystals
« Reply #2 on: April 26, 2023, 08:15:35 AM »
#3. UNKNOWN source, polishing and  documentation sold from the beginning of 2013 by Astimex Standards.  I have a copy of basic mount information up to the end of 2015.

At some point AstStds started using a “fast” Buehler polishing device for both grinding and polishing.  This would certainly cause microfractures in monoclinic crystals. 

This problem has been well documented since 1975.  An excellent assessment was published by John Koivula who did not have access to the journal fulltext at the time. 

« Last Edit: May 03, 2023, 09:34:24 AM by crystalgrower »

crystalgrower

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Re: documentation of RP5O14 crystals
« Reply #3 on: April 26, 2023, 08:24:35 AM »
CURRENT INFORMATION ON SALES

I have limited stocks of most orthorhombic RP5O14 and my living situation has now allowed me to unpack my stocks and microscope from storage.  It will be easier for me to find a place to do syntheses than to access lab services for validation.

My long range plan would be to find an academic home IN CANADA for these materials, to be distributed for  about $20 per crystal.  Please contact me offline if there is an interest in this.